PICT Image Format in Photoshop

PICT, for Macintosh Picture, is a format developed by Apple as its main format for Mac graphics. It is based on the QuickDraw screen language. And although many Mac programs support PICT, I don’t recommend using it for any images that you plan to print. PICTs are notorious for being absurdly slow in the printing department. Today, PICT images are usually used for graphics to be incorporated into slides, screen presentations (such as PowerPoint), multimedia projects, and digital video. PICT supports RGB (with a single alpha channel), Indexed Color, Grayscale, and Bitmap (without alpha channels) image modes. Make sure that QuickTime is running if you want to save a file as a PICT. Here are the options that appear in the PICT File Options dialog box:


-->Resolution: Options for grayscale images are 2, 4, and 8 bits per pixel. Options for color images are 16 and 32 bits per pixel. Under no circumstances should you change the default option. If you do, you delete colors from your image, and you cannot access the compression settings.

-->Compression: The compression settings for PICT are more limited than those for the regular JPEG format. Be aware that the compression scheme used for PICTs causes even more degradation to your image than with JPEGs. To minimize the damage, always select the maximum quality setting.

Camera Raw Format in Photoshop

The Camera Raw file format is the format used by many digital cameras to capture and save image data and also the image’s metadata. In fact, this format captures everything there is to get about an image. Each camera has its own proprietary raw image format. Fortunately, Photoshop can support most camera models, especially higher-end cameras. In this new version of Photoshop, the Camera Raw plug-in has been directly incorporated into the application, which enables you to work more efficiently with camera data. It also enables you to quickly select and apply your Camera Raw settings by batch processing images using the File Browser. Within the plug-in, you will find controls to make adjustments in white balance, exposure, shadows, contrast, saturation, sharpness, and so on. If, by chance, the Camera Raw plug-in doesn’t support your particular camera model, contact Adobe to see if they will be supporting it in the near future.

Camera Raw files utilize a lossless scheme to capture and save image data, similar to TIFFs. This is advantageous, because no data is lost through compression as it is with the JPEG format. Camera Raw files also have the advantage of being smaller than uncompressed TIFFs. Of all the digital camera file formats, only Camera Raw images contain the actual, unadulterated data captured by the digital camera’s sensor (a Charged Coupled Device [CCD] or Complementary Metal-Oxide Semiconductor [CMOS]) without any camera adjustments, filters, and other processing. Many hard-core photographers consider this file format to be the pure digital “negative,” so to speak. They prefer to analyze, manipulate, and adjust the image data themselves rather than leaving those decisions to the mercy of the camera. This file format also prevents the loss of any image data that can sometimes occur when a file is converted from its native format to a more commonly used format like TIFF or PSD.

Your camera may not capture images in the Camera Raw format. It may just allow you to save your images as either JPEG or TIFF. Don’t worry. You’ll be fine with these formats. However, if your camera is capable of saving images in Camera Raw format, you want to check out the capabilities of this plug-in. Because going into detail on each setting found in the plug-ins dialog box is beyond the scope of this book, be sure and visit Adobe. Here you will find a downloadable User Guide, a Q&A file, and great tutorials showing you all you need to know about working with the Camera Raw plug-in.

Photoshop and Photoshop Raw Image Format

Photoshop
Of course, I can’t forget the native Photoshop format (.psd). This format offers a lot of benefits. First of all, along with TIFF and PDF, Photoshop allows you to save layers in your image. The other formats flatten the layers into a single background. This format works well if you are going to spend a considerable length of time working on your image. The Photoshop format also supports all image modes, is the fastest format for opening and saving, and offers all the various save options.

Like TIFF, the Photoshop format uses a lossless compression process, although it’s invisible to you. If you need to open a file in an older version of Photoshop, be sure to save it as a native Photoshop file. Finally, almost all drawing and layout programs now support the importing of Photoshop files.

Photoshop Raw
This format is designed to transfer images among applications and platforms. The Photoshop Raw format can be useful if you want to transfer an image to or from a mainframe computer or other type of device that doesn’t support the standard graphic formats. Don’t confuse it with the Camera Raw format described later in this chapter. The Photoshop Raw format supports CMYK, RGB, and Grayscale images with alpha channels. It also supports Multichannel and Lab Color images without alpha channels. The format allows for any pixel or file size, but it doesn’t support layers.

You may never have to save a file in the Photoshop Raw format. And you may not want to after you read the options involved in saving in this format. The Photoshop Raw format imports and exports files in an uncompressed, binary format. The format does not specify image size, color mode, or bit depth. It is simply comprised of bytes that represent the color information in the image. Each pixel is represented by a brightness value, with 0 being black and 255 being white. The format then includes the total number of color channels in the image, plus any other channels, such as alpha channels. In order to save a file in the Photoshop Raw format you must specify certain settings found in the Photoshop Raw Options dialog box:

-->File Type (Mac OS only): This four-character ID identifies the file type. PRAW is the default ID for the Photoshop Raw format. Leave this default setting.

-->File Creator (Mac OS only): Another four-character ID which tells the operating system which application created the file. Leave the default setting of 8BIM (Photoshop’s code), unless you know the special file creator ID for the application you plan on using the file with. Many Mac applications have file creator IDs registered with the Apple Computer Developer Services group.

-->Header: This parameter specifies how many bytes of information appear in the file before the image data starts. The default setting of 0 means there is no header. If, for example, you enter a 2, two zeros are entered at the beginning of the file as placeholders. When you open the Photoshop Raw format, you can then replace those placeholders with a header. I recommend leaving the value at 0.

-->Save Channels In: Choose between Interleaved Order and Non-Interleaved Order. The default setting of Interleaved Order stores the color data sequentially by pixels. In other words, in an RGB image, the first byte is red for the first pixel, the second byte is green for the second pixel, the third byte is blue for the third pixel. Non-Interleaved Order stores the color data by channel. In this case, the first byte is red for the first pixel, the second byte is also red for the second pixel. Once the red channel is complete, it then goes and saves the green and then the blue channel.

Your choice depends on requirements of the application that will open the file.

PDF Format in Photoshop, the Universal Donor

PDF is the acronym for Portable Document Format, which is the native format of Adobe Acrobat. This format, developed by Adobe, can contain editable text, vector, and raster data. PDF files are often used for electronic documentation that will be downloaded from the Web.

You’ve probably noticed that every Adobe Help document is in PDF format, and if you’re a Web user, you’ve probably downloaded more than a few PDFs. Even the government, notoriously slow to catch on to new technology, has embraced PDF. The military uses PDFs for technical documentation. And all your tax forms are available as downloadable PDFs.

You might be thinking, “So what. I’m into images, not documents.” Well, hold on a second. PDFs can be extremely useful in the imaging world as well. Anyone with a computer running Windows, Mac OS, or Unix can read a PDF. All you need to view a PDF file is Adobe Acrobat Reader, which is available as a free download from the Adobe Web site. If you save your image as a PDF and e-mail it (or post it on the Web as a downloadable file) to a colleague, manager, client, or friend, that person can see your image — colors, fonts, and all — exactly like you see it. The other nice thing about PDFs is that they have an automatic compression process that makes the files small and manageable for mail transfer or loading on the Web.

When you save a file as a Photoshop PDF, you have all the same save options of the native Photoshop format. PDF supports layers and annotations, so select these options if you have either one. It also supports the same image modes as the native Photoshop format. In addition, you can now save 16-bit images as PDF. Here is a description of the other options found in the PDF Options dialog box:

-->Encoding: Choose Zip compression if optimum print quality is an issue. Otherwise, select JPEG at the maximum setting.

-->Save Transparency: When selected, this option preserves any transparent areas in your file. This option is grayed out if your file doesn’t contain transparency or has a spot color channel.

-->Image Interpolation: This option anti-aliases, or slightly softens the edges, of lowresolution images when they are printed. Keep this option selected.

-->Downgrade Color Profile: If you selected ICC Profile (Windows) or Embed Color Profile (Mac) in the Save dialog box in Photoshop Version 4, selecting this option downgrades the profile to Version 2. Select this option if you need to open the file in a program that doesn’t support Photoshop Version 4 profiles.

-->PDF Security: Click the Security Settings button to access the PDF Security dialog box. You can assign a password for opening the file in Acrobat Reader. You can also assign a master password that is required to open the file in Photoshop, which then allows for full access, enabling you to make changes to the image and to the passwords themselves. On the Compatibility pop-up menu, choose the type of encryption — 40-bit RC4, a low encryption level, is fine if you just want to prevent opening the file. Choose a higher level 128-bit RC4 encryption if you want more specific options regarding accessibility (for disabled persons), level of content changes allowed, and allowable printing resolutions. Finally, choose whether you want your user to be able to print or change the document, copy it or extract content, or add or change comments and form fields.

Note that Acrobat 3 and Acrobat 4 users cannot open PDFs with 128-bit RC4 (Acrobat 5) encryption. And similarly, Acrobat 3, Acrobat 4, and Acrobat 5 users cannot open PDFs with 128-bit RC4 (Acrobat 6) encryption.

-->Include Vector Data: Select this option to preserve vector paths. If you have text in your file, select the Embed Fonts option, which ensures that your fonts display correctly on any computer, even if those fonts aren’t installed. But be sure not to use any faux styles or warped text. Embedding fonts increases file size, but it is well worth it. If you select the Use Outlines for Text option, Photoshop converts all your text to paths.

This can be helpful if your fonts aren’t displaying or printing properly, but you won’t be able to select the text or use the Search command in Acrobat. Your text does remain editable in Photoshop, however.

You can now save multiple images into a single, multi-paged PDF document or slide show. This is a great way to e-mail images to coworkers, family, and friends. Choose File➪Automate➪PDF Presentation.

EPS Format in Photoshop

EPS is short for Encapsulated PostScript. PostScript is a page-description language developed by Adobe and used by many printers. The EPS format can contain both vector and raster graphics. EPSs tend to create larger file sizes and do not have a built-in compression scheme like JPEGs or TIFFs. EPS is the recommended file format for creating color separations for high-end, four-color print jobs. This is also the file format to use for images with clipping paths and those with a Duotone color mode. In addition to duotones, EPS supports Lab Color, CMYK, RGB, Indexed Color, Grayscale, DCS, and Bitmap modes. It does not support alpha channels. Finally, EPS is the format of choice for importing to and from drawing programs such as Illustrator, FreeHand, and CorelDraw.

Here are the options when saving in the EPS format:

-->Preview: If you import your EPS into another application, this option provides a lowresolution image for you to view. I recommend choosing 8-bit TIFF, which works on both PC and Mac.

-->Encoding: This option specifies the way an image is sent to the PostScript printer. Choose Binary if you can; it produces smaller files and keeps all original data. If you’re having printing problems, choose ASCII. JPEG compresses the file, but discards data and may cause color-separation problems. Avoid it if possible.

-->Include Halftone Screen and Include Transfer Function: Use these options for offset print jobs. Leave these options to the service-bureau or commercial-printing experts.

-->Transparent Whites: If your image is in Bitmap color mode, this option allows white areas to appear transparent.

-->PostScript Color Management: This option converts the file’s color data to the printer’s color space. I do not recommend selecting this option if you are importing your image into a document that is color managed.

-->Include Vector Data: When selected, this option preserves any vector graphics, such as type and shapes. However, it is preserved only when you import the file into another program. If you reopen the EPS in Photoshop, however, your vector data is rasterized.

-->Image Interpolation: This option anti-aliases (softens the edges) of low-resolution images when printed.

GIF Format in Photoshop

GIF is another file format used for Web graphics. While GIFs support transparency, on the down side you must save GIFs in the Indexed Color mode, which comprises 256 colors or less. Although this is great for making tiny files, it’s not so great for continuous-tone images where the number of colors displayed is critical. Therefore, the GIF format is usually reserved for illustrations (spot illustrations, buttons, logos, and so on) and type with large areas of flat colors and sharp details.

JPEG Format in Photoshop

JPEG, the acronym for Joint Photographic Experts Group, is a file format that uses lossy compression (explained in the “Image Compression” section). The JPEG file format offers 13 compression settings — the higher the quality, the less the compression, and vice versa. JPEG compression is very effective. It can squeeze your file size to practically nothing. JPEG compression works best with continuous-tone images, such as photographs. But because the compression is lossy, I don’t recommend this format for high-end printing and color separations. JPEG supports RGB, CMYK, and Grayscale image modes. It doesn’t support alpha channels.

If you want to post your image on the Web, you have to save it as a JPEG, GIF, or PNG. JPEG works great with photographic images that have a wide range of colors.

JPEG 2000

JPEG 2000 is a new member to Photoshop repertoire of supported file formats. A cousin to standard JPEG, it provides a few more bells and whistles, including better compression rates and more quality settings. In addition to the standard lossy compression algorithms, JPEG 2000 also offers lossless compression and can support 16-bit images, alpha and spot channels, and transparency (8 bit-images only). You can save this format using the following image modes: RGB, CMYK, Grayscale, and Lab Color. If you want to be able to utilize this file format, be sure to install this optional plug-in found on the Photoshop CS Install CD.

One of the coolest features of this format is it supports the use of a Region of Interest (ROI). This feature allows you to selectively choose a region of an image that you can then optimize to ensure the best quality. You save an alpha channel to define that vital portion of the image where detail retention is critical. You can then compress the rest of the image more heavily and with lesser quality, resulting in a smaller file size.

Although praising the qualities of JPEG 2000 is all well and good, be warned that you currently (at press time of this book) need a plug-in to be able to view these files on the Web. In the future, this format is sure to become a standard on the Web and with digital cameras.

Using TIFF Format in Photoshop

TIFF, Tagged Image File Format, is by far one of the best and most useful formats. One of the great qualities of TIFFs is that they are and have always been totally cross-platform. In addition, almost every program on the planet can import TIFFs. Okay, so that’s a slight exaggeration. Almost every word processing, presentation, page layout, drawing, painting, and image-editing program can import TIFFs. This file format works especially well for images that will be printed or color separated.

Photoshop allows you to save layers and transparency and also use various methods of compression. You have the option of having Photoshop warn you that including layers increases your file size. To enable this option, select the Ask Before Saving Layered TIFF Files check box in the Preferences dialog box. Photoshop saves the layers along with a flattened version of the image. Be aware that some applications may display only the flattened version.

It should come as no surprise that the most commonly used format offers a variety of options — all of which are available in the TIFF Options dialog box (shown in Figure 2-4). The following sections give you everything you need to know about your various options so that you can make an informed decision based on your intended uses for the image.

Image Compression
Photoshop offers three methods of compression, besides the option of None, which of course leaves your image uncompressed:

-->LZW: This method has been around for eons and is a lossless compression scheme. This means that data is not deleted to make your file smaller. LZW does an especially good job when you use it to compress images with large areas of a single color. Most programs that support TIFF also support LZW compression, so you can use this method without much hesitation.

If your files are unusually large, compressing them will make your files save and open more slowly. Note that TIFFs can be up to 4GB in file size. Be careful, however, because older versions of Photoshop and other applications don’t support file sizes larger than 2GB.

-->Zip: Zip compression is also a lossless method and is popular in the Windows arena. Like LZW, it works well with images that have large areas of a single color.

-->JPEG: This method, while popular and very effective, is a lossy compression process. When compressing, JPEG deletes data in order to reduce the file size. (That’s where the loss in lossy comes from.) When you open the file again, that deleted data is remanufactured by the program. Over time, this repetitive deleting and remanufacturing can degrade image quality. I recommend that you stick with LZW compression.

Lossy compression can eat away at the quality of your image. Photoshop recompresses a JPEG image every time you save it in JPEG format. During a single edit session, this compression won’t hurt because JPEG works from the on-screen version. But if you close, reopen, and resave the image in JPEG format, degradation occurs. You may not see the results right away, but you will over time. Leave your image in either TIFF or native Photoshop file formats while editing. Then when you’re completely done editing and you need to compress the image, save the file as a JPEG at a high to maximum quality setting.

Byte Order
Specify whether you want to save the TIFF for a Mac or a PC. If you want to be able to use the image on both platforms, select IBM PC. Macs are much more forgiving when exchanging files.

Save Image Pyramid
This option allows you to save multiple resolutions of an image. The top of the pyramid is the lowest resolution, and the bottom of the pyramid is the highest resolution. If the program supports them, you can choose to open any of the resolutions. Currently, only Adobe InDesign supports image pyramids. Photoshop can open only the image at the highest resolution within the file. I recommend leaving this option deselected.

Save Transparency
Select this option to preserve transparent areas when the TIFF is opened in other applications. Of course, those applications must also support transparency. If you open a TIFF with transparency in Photoshop, the transparent areas are always preserved whether or not you select the option.

Layer Compression
If you want to save the layers in your file, Photoshop saves a flattened version along with your layered version to ensure compatibility with programs that don’t recognize layers. If you retain the layers, you have the choice of RLE (Run Length Encoding) or Zip compression. Because RLE compression is also lossless, you have the choice of faster saves (RLE) or smaller files (Zip). The last choice is for Photoshop to discard the layers, thereby flattening the image and then saving it as a copy. Your original layered file also remains intact.

Choosing the Right File Format in Photoshop

A critical component in saving a file is choosing the file format. The file format is the way the file’s data is represented and saved. Photoshop generously offers numerous file formats to choose from. Some you’ll use frequently, and others you’ll never set eyes on. I provide quite a bit of detail on the formats you’ll use most frequently, and throw in a brief description of those you’ll encounter only once in a blue moon (if at all).

Note that if a file format doesn’t appear in the Open, Save, or another dialog box, you may need to install the plug-in for that particular format.

Using the Conditional Mode Change Command in Photoshop

Photoshop enables you to specify instances where one mode changes into another so that you can utilize the conversion command in an action. Briefly, an action is a collection of recorded and saved commands that you can replay again and again.

Sometimes when you incorporate a mode conversion as part of an action, you get an error message because the file you’re opening may not have the same mode you specified as the source mode in the action. For example, you may have specified CMYK as your source mode in the action. But if the action opens a file in Grayscale mode, you get an error message, because the Grayscale mode of the file doesn’t match the CMYK source mode. The Conditional Mode Change command takes care of this problem. Here’s what you do to add this command to your action:

1. Start creating and recording your action.
2. Choose File➪Automate➪Conditional Mode Change.
3. In the Conditional Mode Change dialog box select the mode(s) you want as valid for the source mode. Other options include the All or None buttons to select all modes or no modes.
4. Select your desired target mode from the Mode pop-up menu.
5. Click OK.
If all goes well, Photoshop incorporates the Conditional Mode Change command as a step in your action.

Converting to a Different Color Mode in Photoshop

Sometimes, your image starts out in one color mode and then you find you need to convert the image to another mode. Maybe you need to strip the color out of an image you’re submitting to the local newspaper. Or maybe you need to convert your RGB image to CMYK to get it ready for an offset print job.

When you convert modes, you are permanently changing the color values in your image, so save a backup image just in case. The next few sections offer pointers for the most common conversions you’ll make.

Converting from RGB to CMYK
As I mention several times in this book, CMYK is the image mode necessary for high-end composite printing and offset printing. You will first want to perform all your necessary image-editing tasks in RGB mode for the following reasons:

-->The image size is smaller because RGB mode has only three channels.
-->The RGB color space provides more device independence because it isn’t reliant on inks.
-->You have full accessibility to filters.
-->RGB mode provides a large color gamut, so Photoshop preserves more colors after it makes image adjustments.

When you’re finished editing the image in RGB mode, you can convert the image from RGB to CMYK (you can perform any fine-tuning in CMYK mode if necessary). If you’re new to this procedure, you may be surprised at what can result. Because the color gamut (range of colors) of the RGB model (16.7 million) is much larger than that of CMYK (approximately 55,000), you may see a color shift, which may range from slight to major.

The extent of the shift depends on the colors in the RGB image and how many of them are out of gamut. Photoshop replaces RGB colors that are out of gamut with the closest match available within the CMYK gamut, often replacing the electric blues, fiery reds, and sunny yellows with duller, muddier CMYK equivalents. Unfortunately, you can’t do anything to prevent this.

It is just the way of the world of color. However, if you can select colors (rather than acquiring them from a scan), be sure that you don’t select any colors that are out of gamut to begin with.

If you want to see what the effects of your CMYK conversion will be without actually converting, choose View➪Proof Setup➪Working CMYK. This view is referred to as a soft proof — previewing on-screen how your image will look on various output devices or various modes.

Converting to Grayscale
You can convert a color image to grayscale a multitude of ways. The next few sections cover a few that you may want to try out. You can also use the Channel Mixer to create custom grayscale images.

Quick and dirty method
Choose Image➪Mode➪Grayscale. Photoshop then asks you whether you want to discard color information. Click OK. Photoshop merges the RGB or CMYK channels into one black channel, and you now have a grayscale image. You may find that although this method does the job in stripping color from your image, you may be left with an image that is flat and lacking contrast. You can apply a Levels adjustment (choose Image➪Adjustments➪Levels) to boost the contrast, or you can try one of the other conversion methods. If your image contains multiple layers, Photoshop asks whether you want to merge your layers. If you want to keep your layers, click the Don’t Merge button.

Be aware that you can no longer apply color to your image. If you choose a color in the Color palette, the color appears gray in the foreground and background color icons. If you want to apply color to your grayscale image, you must convert it back to RGB or CMYK mode.

Lab Color mode method
Choose Image➪Mode➪Lab Color. As mentioned earlier, converting to Lab Color mode converts the channels into a lightness channel and a and b channels containing ranges of color. Delete the a channel. The b channel then changes its name to Alpha 2. Delete the Alpha 2 channel. That leaves you with the lightness channel, which is now named Alpha 1. Choose Image➪Mode➪Grayscale. Your color image is now a grayscale one. Note that if your image contains multiple layers, Photoshop flattens the layers when you convert to grayscale. Make sure that you finish all your edits requiring layers before you convert to grayscale. This method most likely provides a better grayscale image than the quick and dirty method.

Best channel method
If you look at the individual channels in the image, one often stands out as being a very good grayscale image by itself. You may find that the red channel provides a good grayscale image when the subject is people, because humans have a lot of red in their skin. Or you may find the green channel crud picked up from scanners finds its way into the blue channel.

In the Channels palette, select each channel and view its contents. Find the channel that looks the best and then choose Image➪Mode➪Grayscale. Photoshop asks you if you want to discard all the other channels. Click OK. Like with the Lab Color method, if your image contains multiple layers, Photoshop flattens the layers when you convert to grayscale.

Converting to Indexed Color
You may need to convert your RGB or CMYK images to Indexed Color to save them as GIFs and prepare them for posting on the Web. The main issue to be aware of is that the Indexed Color mode contains only 256 colors (or even less). That is a far cry from the thousands or millions offered by CMYK and RGB images. If color is critical, you may want to reconsider making the conversion and instead leave or convert your image to RGB mode.

The Indexed Color mode cannot support layers, so again, be sure to perform all necessary editing functions before making the conversion. You also lose all capabilities to anti-alias any portion of your image, including your text, which can lead to hard, jagged edges that you may not want. The bottom line is, perform all of your editing functions in another mode and convert to Indexed Color only when you’re ready to save the image for the Web. When converting to indexed color, you have options for specific palettes, numbers of colors, dithering. These options affect the appearance of the image.

Selecting a Color Mode in Photoshop

Every file has a color mode, also called an image mode or just plain mode. To determine the color mode of an image, look in the title bar of the image window or choose Image➪Mode. Color modes define the color values used to display the image. Photoshop offers eight different modes and allows you to convert images from one mode to another. The color mode you choose for a particular image depends on a couple of factors:

-->The file format you plan to save it in. Some modes call for specific file formats. You may find that a certain format is unavailable because your file isn’t in the appropriate color mode.

-->The end use for the image. Do you plan to post the image on the Web? Or are you putting it in a brochure that will be offset printed?

The next few sections provide a brief description of each mode and any file format or usage connections. For examples of some modes, in full, living color, be sure to check out Color Plate 2-2.

Color modes affect the number of colors that are displayed, as well as the size of the file and the number of channels. Each mode is also represented by one or more channels, where the color data is stored. Grayscale images have one channel — black. CMYK images have four channels — cyan, magenta, yellow, and black.

RGB Color
Uses: RGB is the gold standard for most scanners, all monitors, and some desktop inkjet printers. And it’s the primary color mode (with Indexed Color being secondary) to use with any images to be viewed on-screen (whether on the Web or in any kind of multimedia presentation).

File formats: RGB can handle just about every format except GIF.
RGB can be considered the default color mode of Photoshop. RGB images contain values of 0–255 for each of three colors — red, green, and blue. With 8 bits of color information for each of the three colors, these 24-bit images can reproduce up to 16.7 million colors on-screen. And 48-bit images (16 bits per color) can display even more. Most scanners also scan images in RGB, all monitors display in RGB, and some desktop inkjet printers prefer to print RGB (rather than CMYK) images. Remember that the RGB mode in Photoshop varies according to the RGB Working Space setting you have selected in the Color Settings dialog box.

CMYK Color
Uses: CMYK is the standard for images that are color separated for offset printing.

File formats: CMYK can handle just about every format except GIF.
CMYK images contain a percentage of one or more of four-process color inks — cyan, magenta, yellow, and black. Darker colors have higher percentages, whereas lighter colors have lower percentages. Pure white is created when all four colors have a value of 0%. Many other composite printing devices also require images to be in CMYK mode. Again, like RGB mode, remember that the CMYK mode in Photoshop can vary according to the CMYK Working Space setting you have selected in the Color Settings dialog box.

Make sure that you do all of your image editing in RGB mode, where you have access to the full range of filters. When you complete your editing, convert the image from RGB to CMYK.

Grayscale
Uses: Grayscale mode is for black-and-white (and all shades of gray in between) images.

File formats: All of the most commonly used file formats accept Grayscale mode.
Grayscale images contain up to 256 levels of gray. Each pixel has a brightness value ranging from 0 (black) to 255 (white). You can scan an image in Grayscale mode, or you can convert color images to grayscale. If you convert a color image to grayscale, Photoshop discards all the color information, and the remaining gray levels represent the luminosity of the pixels.

You can also convert a grayscale image to a color image, which, while it doesn’t convert your grayscale image to color, it allows you to apply color on top of the grayscale image.

Monotone, Duotone, Tritone, and Quadtone
Uses: Because printing presses can print only about 50 gray levels per ink color, duotones, which use two to four inks, are used to increase the range of tones of grayscale images. Duotones are often created by using black and spot colors (premixed inks), although you can also use process colors.

File formats: The only file formats that can save duotones, tritones, and quadtones are native Photoshop, Photoshop 2.0, EPS, PDF, Large Document Format, or Photoshop Raw. These modes create one-color, (monotone), two-color (duotone), three-color (tritone), and four-color (quadtone) images. Note that Photoshop lumps all the various “tone” modes under duotone. You will find a pop-up menu in the Duotone options dialog box where you can select the various options. Unlike RGB and CMYK images where the components of the image display with different colors, the monotones, duotones, tritones, and quadtones have the colors mixed throughout the image. The colored inks are used to reproduce tinted grays, not the different colors you find in RGB and CMYK images.

To access the Duotone mode, you must first convert the color image to grayscale by choosing Image➪Mode➪Grayscale. Then choose Image➪Mode➪Duotone. In the dialog box that appears, choose Monotone, Duotone, Tritone, or Quadtone from the pop-up menu. Next, select ink colors — either spot or process — by clicking the swatches. Finally, you can adjust the curves settings and tell Photoshop how to distribute the ink(s) among the various tones.

Note that you do not have access to the individual color channels in Duotone mode. The only manipulation that you do is with the curves settings. If you are new to these modes, you need to know that Photoshop offers numerous preset duotones, tritones, and quadtones. To access these presets, click the Load button and go to the Duotones folder (which is located in the Presets folder in the Photoshop folder).

Indexed Color
Uses: Indexed Color mode is primarily for Web graphics and multimedia displays.

File formats: Indexed Color mode supports a variety of formats, with GIF being the most popular.
Others formats supported include Photoshop, Photoshop 2.0, Photoshop Raw, BMP, EPS, ElectricImage, Large Document Format, PCX, PDF, PICT, PICT Resource, PNG, Targa, and TIFF. Indexed Color mode uses 256 colors or less; what graphics aficionados call 8-bit color. When you convert an image to indexed color, Photoshop builds a Color Lookup Table (CLUT), which stores and indexes the color. (Note the Color Table option in the Mode menu.) If a color in the original image isn’t in the table, Photoshop chooses the closest match or makes a new one from the available colors. The small amount of colors reduces the file size, which is why the GIF file format, the preferred format for Web graphics, uses this mode. The Indexed Color mode does not support layers, and editing capabilities are limited.

Lab Color
Uses: Lab Color mode provides a consistent color display, which is ideal for high-end retouching of images.

File formats: You can save an image in Lab Color mode in native Photoshop, Photoshop Raw, EPS, TIFF, PDF, JPEG 2000, Large Document Format, or Photoshop DCS 1.0 and 2.0 formats. You can save images containing 48 bits (16 bits per channel) in Photoshop, Photoshop Raw, Large Document Format, and TIFF formats.

Lab Color mode is usually thought of as the internal color mode Photoshop uses when converting from one color mode to another — for example, when going from RGB to CMYK. It is also the mode preferred by color-retouching experts because it is considered to be device independent (it appears consistent on various devices). Lab Color mode consists of a lightness channel and two additional channels, a and b, which contain the range of color from green to red (a) and blue to yellow (b).

Bitmap
Uses: This mode is best for scanned line art and signatures (your John Hancock).

File formats: Photoshop, Photoshop 2.0, EPS, TIFF, PDF, BMP, PNG, GIF, PNG, PCX, PICT, PICT Resource, Portable Bitmap, and Wireless Bitmap. Bitmap images contain pixels that are either black or white, exclusively. You must convert color images to grayscale before you can access Bitmap mode. Upon choosing Image➪Mode➪Bitmap, a dialog box appears, offering options for resolution and method. The various methods give different appearances so try each one to see which you prefer.

If you save a file in Bitmap mode as an EPS you can convert the white areas in the image to transparent areas. This allows you to overlay the file over a background containing color or an image, and only the dark pixels show.

Multichannel
Uses: Multichannel mode is for special printing needs or as an intermediate mode when converting between different color modes.

File formats: The only file formats available for multichannel images are native Photoshop, Photoshop 2.0, Photoshop DCS 2.0, Large Document Format, or Photoshop Raw formats. The Multichannel mode comprises multiple grayscale channels, each containing 256 levels of gray. Whenever you delete or mix channels, you end up with a multichannel image. You can also convert any image with more than one channel to this mode. In a multichannel image, each channel becomes a spot channel, with 256 levels of gray.

Knowing CMYK basics in Photoshop

The CMYK color scheme is based on the light-absorbing quality of ink on paper. In theory, a white light hits these inks. Some visible wavelengths are absorbed, or subtracted, while others are reflected back to your eyes. CMYK images comprise various percentages of only four colors of ink — cyan, magenta, yellow, and black. These colors correspond to the inks used in the offset printing process.

Cyan, magenta, and yellow are called subtractive colors. Technically if you combine these three colors of ink, you produce black. But because of ink impurities, you actually end up with a nasty brown color. (That’s why we add K, or black to produce black.) CMYK colors are also known as process colors. Mixing colors in CMYK produces darker colors. Setting all four inks to 0% produces pure white.

Subtractive and additive colors are complementary. This means that each pair of subtractive colors creates an additive color and each pair of additive colors creates a subtractive color.

Knowing RGB Basics in Photoshop

When you view an RGB image, you are looking at an image comprised of three colors — red, green, and blue. These colors are:

-->The primary colors of light
-->The colors that correspond to the three types of cones inside your eyes
-->The colors that comprise white light from the sun
-->The colors your monitor uses when displaying images

Mixing these three primary colors can yield up to 16.7 million colors. In Photoshop, each of these colors resides in a color channel in the image. Photoshop looks at a color image in terms of its channels — individual bands of 8-bit grayscale images. When you view the channels individually in Photoshop, you can visually see that each channel appears as a grayscale image made up of light-, medium-, and dark-colored pixels (assuming that you have deselected the Color Channels in the Color check box). RGB images have three bands, and CMYK images have four bands. Each one of these bands, or grayscale images, is a channel, or more specifically a color channel. When you view the channels together, the pixels from each channel mix to form colors, which give you a composite, or full-color image.

Photoshop assigns each pixel a brightness value ranging from 0 (black) to 255 (white). These grayscale pixels from each channel mix together to form colors, which in turn provide you with a composite color image. Here are some color channel examples to help you see how the RGB system works to create so many different color variations:

-->A light-colored pixel from the green channel, a dark-colored pixel from the red channel, and a dark-colored pixel from the blue channel combine to give you a green pixel.
-->A value of 255 from all three channels produces white.
Because RGB colors combined at 255 create white, they are known as additive colors.
When you view this white on your computer monitor, for example, it transmits all visible wavelengths back to your eyes.
-->A value of 0 from all three channels produces black.
-->If all three values are equal, a neutral gray is produced.
-->A medium-dark pixel from the red channel, a black pixel from the green channel, and a light-colored pixel from the blue channel combine to produce purple.
-->Mixing colors in RGB produces lighter colors. Try playing with the RGB color sliders in your Color palette and mix your own colors to see this concept in action. Remember that the right side of the slider (the higher numbers) represents light, and the left side of the slider (the lower numbers) represents dark.

Choosing Color Modes and File Formats in Photoshop

In addition to choosing a size and resolution (discussed in the previous chapter), you need to decide on an image mode and file format for your image. This decision is usually based on the final use for the image. Will it be imported into a page layout program and then offset printed? Will it be posted on a Web page? Will it be used for a newspaper article? When you know an image’s final destination, you can make intelligent choices of which color mode and file format are best. This section gives you some background information to help you make those choices so that you don’t end up having to do extra work, spend extra time, or waste extra money.

Understanding Color Theory
You can find many books, most of them detailed and lengthy, devoted to a single subject — color — and written by bona fide color experts who spend their days analyzing complex color algorithms for fun. I recommend owning at least one heavy-duty tome on color, even if its main function is to act as a paperweight.

Even as an occasional reference, a book on color theory is essential if you’re serious about using Photoshop in your daily activities. In this chapter, I provide you with the minimalist’s take on color theory.

Using the Crop and Straighten Photo Command in Photoshop

Because cropping is one of the most commonly used Photoshop features, this version comes equipped with an additional cropping mechanism.

Choose File➪Automate➪Crop and Straighten Photos. Photoshop then looks for rectangular areas in your document, extracts each one into its own document, and then straightens those individual images.
The Crop and Straighten Photos command is fabulous if you want to save time by scanning multiple images initially into one document (and the command works on single images as well). This command is a real manual labor time saver, and I wholeheartedly endorse it.

Sure-fire cropping tips in Photoshop

Even though cropping is about as simple an image-editing maneuver as you can get, you need to know about a few other options:
-->If you need a nonrectangular cropping marquee, select the Perspective check box in the Options bar. This allows the corner handles to move independently. Cropping with Perspective selected can help to rectify images that have keystone distortion, which occurs when you photograph an image from an angle rather than straight on.

-->The Front Image option enables you to crop one image so that it’s the exact same size as another image. Open two images and crop the first one. Click Front Image. Photoshop enters the width, height, and resolution values from the first image in the Options bar. Drag the Crop tool on your second image and adjust the marquee as desired. Double-click inside the marquee. Photoshop automatically crops your second image to match your first. The Front Image command is also available in the Options bar only before you drag your cropping marquee.

-->If your image doesn’t contain any layers — that is, it consists only of a background — any cropped areas are permanently deleted from your file. However, if your image consists of one or more layers, you have the choice of deleting or hiding your cropped area. Delete eliminates the cropped areas, whereas Hide just hides the cropped area. You can see the cropped area if you move the layer with the Move tool. Another way to see the hidden area is to choose Image➪Reveal All. Photoshop expands the canvas to show all areas in all layers. These options are available only while the crop marquee is active.

-->If you want to crop an image to an exact measurement, enter a value in the Width, Height, and Resolution text boxes in the Options bar. Note that these options are available only when the Crop tool is active and you haven’t yet dragged a cropping marquee. You can still freely drag and adjust the cropping marquee. When you commit the crop, your image matches the physical dimensions you specified. You can enter values in just one, two, or all three options. But again, be careful about the value you use for the Resolution setting. Remember, resampling is not a good thing. To remove the entered settings, click the Clear button in the Options bar.

Using the Trim Command in Photoshop

The fabulous Trim trims away transparent or solid-colored areas around your image. Choose Image➪Trim, and a dialog box appears. Select Transparent Pixels (for layered images), Top Left Pixel Color, or Bottom Right Pixel Color as a basis for the trim. Next, instruct Photoshop to trim away the Top, Bottom, Left, or Right side(s) from the image. This command works great for quickly eliminating black-and-white borders around images.

Cropping with the Marquee Tool in Photoshop

If you get bored using the Crop tool, you can also crop a selected area by choosing Image➪Crop. Simply make a selection with any of the tools and then choose this command. Although using the Rectangular Marquee tool for your selection makes the most sense, you don’t have to.

You can use Image➪Crop with any selection — circular, polygonal, kidney bean, even feathered. Photoshop can’t crop to those odd shapes, but it gets as close to the outline as it can.

Cropping an Image in Photoshop

Even a novice photographer knows that cropping an image can make a composition stronger. Cropping entails cutting away background clutter or endless expanses of empty space in order to focus in on your desired subject.

This simple process can transform a ho-hum photograph into a visually exciting one. I mean, it doesn’t take an Ansel Adams to figure out which image is stronger. (It would be even better if the fence weren’t in the background, but hey, that’s nothing that a little Photoshop retouching can’t take care of.

Using the Crop tool
The most popular way to crop an image is by using the Crop tool. This simple tool is as easy and effective to use as a T square and X-ACTO knife, and without the possibility of bodily injury. Select the Crop tool or press C on the keyboard and then follow these steps:

1. With the Crop tool, drag around the part of the image you want to keep and then release your mouse button.
As you drag, a marquee (a dotted outline) appears displaying the cropping boundaries. Don’t worry if your cropping marquee isn’t exactly correct. You can adjust it in the next step. Notice how the area outside the cropping marquee appears darker than the inside, in order to better frame your image. Adobe calls this a shield. You control the color and opacity (the amount of transparency) of the shield by adjusting the settings in the Options bar. If, for some strange reason, you don’t want the shield, deselect the check box.

2. Adjust the cropping marquee by dragging the handles.
The small squares on the sides and corners of the cropping marquee are called handles. When you hover your mouse over any handle or the marquee itself, your cursor changes to a double-headed arrow, indicating that you can drag. If you drag the handles outside the image boundary, Photoshop adds a
canvas around the image when you crop.

To move the entire marquee, position your mouse inside the marquee until you see a black arrowhead cursor and then drag. Adjust the marquee until you’re satisfied. You can also drag the origin point to change the axis of rotation.

If you move your mouse outside the marquee, the cursor changes to a curved, double-headed arrow. Dragging with this cursor rotates the marquee. This feature can be extremely useful when you need to rotate and crop a crooked image. By using the Crop tool, you can perform both commands in one step and often more quickly and accurately. Just be aware that rotation, unless it’s in 90-degree increments,
resamples your image, which, if done repeatedly, can damage your image (see the beginning of this chapter for more on resampling). So it’s best to try to get the rotation right the first time around.

3. Double-click inside the cropping marquee.
You can also just press Enter (Return on the Mac) or click the Commit (check mark icon) button on the
Options bar. Photoshop discards the area outside the marquee. If you want to cancel the crop, just press Esc or click Cancel (the slashed circle icon) in the Options bar.

Changing the Canvas Size in Photoshop

I’ve probably harped on you to the point that you’re slightly paranoid, or at least ultraconscious, of using the Image Size command. Well, you can relax now because the Canvas Size command is as safe as can be. Unlike the Image Size command, which enlarges or reduces the dimensions or resolution of your image, the Canvas Size command merely changes the size of the canvas, or page, on which the image sits.

When you increase the size of the canvas, Photoshop fills the expanded area outside the image with your chosen color. Increasing your canvas size can come in handy if you are trying to add a frame or border around your image. If you make the canvas smaller, Photoshop crops (cuts away) the image.
Here are the quick and easy steps to changing your canvas size:

1. Choose Image➪Canvas Size.
The Canvas Size dialog box appears. The current size of your canvas appears at the top of the dialog box.

2. Enter new values in the Width and Height text boxes.
You can also change the unit of measurement by using the pop-up menus. Select the Relative check box to specify an amount of space for Photoshop to add around your image. This feature is handy when adding equal amounts of canvas around images with fractional measurements.

3. Specify your desired anchor placement.
The anchor shows how the image sits inside the canvas. By default, Photoshop centers the image and adds the canvas around it. Click any of the other eight squares to have Photoshop add the canvas asymmetrically around the image.

If you reduce either the Width or Height value and click OK, an alert box appears asking if you really want to proceed because you will be clipping the image. This is actually another way of cropping an image, albeit not one you will use everyday. Photoshop has more exact ways of cropping an image (see the next section). However, this method can occasionally come in handy when you want to crop your image on one or more sides by a certain number of pixels. For example, sometimes cropping (using the Crop tool described in the next section) a one- or two-pixel-wide row or column along the edge of an image is difficult.

In this case, use the Canvas Size command and specify a value for the Width and/or Height that is a couple of pixels smaller than your original. Pesky problem solved.

4. Choose your canvas color from the Canvas Extension color pop-up menu and click OK.
No longer do you have to be diligent in selecting a background color before you initiate the canvas size command. Photoshop now offers you the option of choosing the color you want for your newly expanded canvas. Choose from Foreground, Background, White, Black, Gray or Other. If you select Other, Photoshop transports you to the Color Picker where you can choose any color you desire. Note that the small swatch to the right of the pop-up menu displays the current background color. You can also click this swatch to access the Color Picker.

Resizing Images with the Resize Image Wizard in Photoshop

You find the Resize Image Wizard (Resize Image Assistant on the Mac) on the Help menu on the Photoshop menu bar. When selected, the Wizard/Assistant dialog box appears and asks you questions about your intended use for the image. The wizard/assistant then guides you through the image-sizing process. If you happen to choose options that the wizard doesn’t like, you get a warning that your changes are likely to lower your image quality. You can then go back and try another setting.

The Resize Image Wizard is more for beginners and doesn’t offer quite the control that the Image Size dialog box does. In addition, you can’t see all your options on one screen and must continually go back and forth between screens when entering different values.

When you finish changing settings and choosing options, the wizard/assistant creates a new file called Resize Wizard_1 (Resize Assistant 1 on the Mac), leaving your original unharmed. Like any kind of wizard, this one is pretty savvy, but I recommend having a firm understanding of proper output resolution (see the beginning of this chapter for info on that topic) before you use the wizard/assistant. And actually with that firm understanding, you can do manually everything the wizard/assistant can do and more. Remember the old adage, knowledge is power.

Although using the Resize Image Wizard is fine, try to avoid using File➪Automate➪Fit Image. When I see a dialog box having to do with image sizing that only contains two text boxes, it’s an immediate red flag! This command resizes your file as close to your entered dimensions as possible, while maintaining the same proportions. But in order to do so, Photoshop enlarges or decreases your image while leaving the resolution the same. And if you’ve read earlier sections of this chapter, you know this is also called resampling — not a nice thing in image-editing circles.

A Potpourri of Image Size Do’s and Don’ts in Photoshop

Here are some tips and tricks to keep in mind when you’re messing around with image size and resolution settings:
-->Use the Unsharp Mask filter when you resample. If you resample your image, either up or down, it is sometimes helpful to apply an Unsharp Mask filter (choose Filter➪Sharpen➪Unsharp Mask). This filter
heightens the contrast between pixels to give the illusion of sharpening or forcing the image more in focus.

-->You can always look without touching. If you don’t want to change the resolution or size of your image, but just get its vital statistics, use the file information box at the bottom of the application window (document window on the Mac). Press Alt (Option on the Mac) and click your mouse button over the file information box. You can see the width, height, channels, and resolution of the document.

-->Don’t change your settings — just use Print with Preview. If you want to leave the size and resolution settings untouched, but need to print your image at a different size, use the Print with Preview command.

-->Try starting out with the proper dimensions. It goes without saying, but I’ll say it anyway. You want to try to enter the proper dimensions and resolution when creating a new document. You don’t want to find yourself in the unfortunate situation of creating your file at 72 ppi, spending hours getting it just perfect and then remembering that you were supposed to prep it for print and really needed it to be 300 ppi. Resampling your image from 72 ppi to 300 ppi is going to make it go from perfect to, well, far less than that. And when scanning an image, make sure that you scan it at a high enough resolution that if you need to enlarge the dimensions, you can do so without changing the pixel dimensions.

-->Don’t use a higher resolution than you need. All you do is create an unnecessarily huge file with a slower print time. In addition, the output device may not be able to reproduce all the detail in the image. In some cases, it may actually make your printout look darker and muddier.

-->Look no further than this blog. Use the handy, dandy table of recommended resolution settings for a variety of output devices.

If you have to downsample your image significantly, for example to 25% of its original size, you get better results if you do several successive 50% downsamples, applying a Unsharp Mask filter on the image in between each image sizing. To remove pixels from an image, follow the steps in the preceding section and change the image settings accordingly.

Taking Pixels Out of an Image in Photoshop

As I mention earlier, when you downsample you eliminate pixels and therefore delete information and detail from your image. Although I have emphasized the pitfalls of resampling up, you can sometimes damage your image by downsampling, as well.

Granted, downsampling is sometimes necessary when converting high-resolution print graphics into Web graphics. For example, you may be forced to take images used for a corporate brochure and repurpose them into content for the company’s Web site. You probably won’t notice much degradation in image quality because the images are just being viewed on-screen. In addition, downsampling can occasionally camouflage the moiré patterns caused by scanning halftones. However, you can downsample to the extreme where the images look horrid even on-screen. But just remember, you should never need to make an image smaller than 72 ppi.

Adding Pixels to an Image in Photoshop

To add pixels to an image, follow these steps:
1. With your desired image open, first choose Image➪Duplicate to make a copy of your original. With the duplicate active, choose Image➪Image Size.
This is where the havoc happens.
Be careful!

2. Make sure that the Resample Image option is selected.

3. Enter a higher value for the resolution, and if desired, enter a higher value for the width or height.
I entered a resolution of 300 ppi and a width of 8 inches.
Note how the pixel dimensions increased dramatically as did the file size (from a mere 149K to 10.9M).
The Width and Height under Pixel Dimensions are now text boxes into which you can enter values as well. They are no longer fixed values as they were when Resample Image was deselected.
Leave your Interpolation method set to Bicubic. If you get all discombobulated when working in the dialog box, press Alt (Option on the Mac). The Cancel button will change to a Reset button. Click it, and you’re back to where you started.

4. Click OK.
Photoshop now goes through its interpolation ritual and churns out a newly resampled image. Do a side-by-side comparison to the original, looking at both at 100% view. Your original should look better than the resampled image. Notice the overall blurriness and goopy edges that are an unfortunate side effect of interpolation.

Resampling Images in Photoshop

Resampling means you are changing the pixel dimensions of an image. When you downsample (or resample down), you are eliminating pixels and therefore deleting information and detail from your image. When you resample up (or upsampling), you are adding pixels. Photoshop adds these pixels by using interpolation. Interpolation means Photoshop analyzes the colors of the original pixels and “manufactures” new ones, which are then added to the existing ones.

You can specify the interpolation method in the Image Size dialog box. The default that appears in the dialog box is based on the interpolation method you specified in your General Preferences dialog box. Here are your five choices:

-->Nearest Neighbor: This method is fast and provides for the smallest file size, but it is less precise and therefore of the lowest quality. This method works by copying the color of the nearest pixel. It can result in jagged edges, so use it only for images with non-anti-aliased edges (hard edges).

-->Bilinear: Considered a medium-quality method, it works by averaging the color of the pixel above, below, and to the right and left of each pixel.

-->Bicubic: This method is the slowest but most precise. It averages the color of the pixel above and below and the two on the right and left of each pixel. It provides a smoother transition between pixels but also increases the contrast between pixels to reduce blurriness.

-->Bicubic Smoother: Like Bicubic, but provides an even smoother transition between pixels and therefore increases the amount of blurriness. A good method to use when upsampling images. Can slightly affect the sharpness of the image.

-->Bicubic Sharper: Also similar to Bicubic, but applies less anti-aliasing and therefore less blurriness as well. This method applies just a little softening to pixel edges. This is a good method when downsampling an image. Bicubic Smoother and Bicubic Sharper are new to Photoshop CS.

If you really must resample, I recommend leaving the method set to Bicubic Smoother. Notice I said if you really must. Here are some reasons why you might choose to add or delete pixels:

-->You no longer have access to the original artwork, which you could rescan at the proper resolution and size.
-->You no longer have access to the original high-resolution version of the file.
-->You absolutely cannot substitute the low-resolution image with another of higher resolution.

Resampling isn’t a recommended activity, especially when it pertains to upsampling. I mean as smart as Photoshop is, having to manufacture pixels out of the blue is not an exact science. Your image tends to lose detail and sharpness and get blurry and mushy. The bottom line is your resampled image never looks as good as the original. Downsampling isn’t as scary. Even though you are deleting pixels, and therefore detail, the degradation is virtually undetectable with the eye.

Using the Image Size Command in Photoshop

A time will come when you need to mess with the resolution or dimensions of an image. You may want to change the file size, or you may simply need to make sure that the resolution is appropriate for printing or some other paper output. Or you need to adjust the dimensions so that they’re just right for viewing on-screen. And sometimes — only sometimes — you may need to add or delete pixels.

Or you need to change the width, height, and/or resolution of your image for printing or some other kind of output. Photoshop, being the powerhouse that it is, certainly allows you to do so with the Image Size command found on the Image menu. Follow these steps to resize your image:

1. Open the image and then choose Image➪Image Size.
The Image Size dialog box opens. This is where the magic happens.

2. Note the current pixel dimensions of your image and the resulting file size.
Mine shows 1536 pixels in width and 1024 pixels in height for a file size of 4.5M.

3. Also note your current document size.
This is the size of your image when it prints on paper. Mine shows a width of 21.333 inches and a height of 14.222 inches with a resolution of 72 ppi. A resolution of 72 ppi isn’t adequate for printing purposes. I will be able to see some pixelation (visible little squares) on my printout. Therefore, I need to reduce the size of the image so that my total pixels are spread out over a smaller area, making them more densely packed.

3. Make sure that the Resample Image check box is deselected and then enter a new value for the width in the Document Size area.
Don’t worry about the definition of resample; I explain it in the next section. I entered a value of 5.12 inches. Note how my height value automatically changed to 3.413. That’s because the Constrain Proportions check box is selected, as indicated by the chain and bracket icon. Notice that the check box is also grayed out. If the Resample Image option is deselected, the Constrain Proportions option is unavailable. Nine times out of ten, you’re probably going to want your image to stay proportional. You can also change your units of measurement by choosing from the pop-up menu.

4. Note how the resolution automatically changed based on what you entered in Steps 3 and 4.
In my example, my resolution went from 72 ppi to 300 ppi. When you do not have Resample Image selected, your pixel dimensions remain unchangeable (note how there is no text box for you to enter new pixel dimension values). Therefore, when you enter a smaller width or height value, the resolution must increase in order to accommodate all the pixels in the image. Similarly, if you enter a new resolution value (rather than a width value as I did), Photoshop then adjusts the width and height values in order to accomplish the same thing.

Before you close this dialog box, I would be remiss in not telling you about the Auto button. This is Photoshop’s way of giving you a suggested resolution setting based on your screen frequency. Don’t worry about it for now. But if you feel the burning need to know about screen frequencies.

Again, before you click OK, I want to fill you in one new option. The Scale Styles option allows you to scale or not scale any effects or styles that you have applied to your layer(s). Note that this option is available only if you have checked Constrain Proportions.

6. Click OK.
You won’t notice any difference in the way your image appears on-screen because you haven’t added or deleted any pixels; you’ve merely compacted them into a smaller space. Congratulations! You have just safely resized your image. You can proudly say, “No pixels were harmed in the making of this image.”

Photoshop: Resolution, dimension, and size in raster images

Every raster image has these physical attributes resolution, dimension, and size. Size takes on two personalities. You have the file size, which is a result of the pixel dimensions, and you have print size, which is the width and height of an image.

These attributes are interrelated. Change any one and at least one of the other attributes is affected also. The file size of a raster image is determined by the pixel dimensions — the number of pixels along the height and width of the image. Photoshop dialog box lists all the vital statistics of an image that takes up 176K of space and is 200 pixels wide and 300 pixels high. Just multiply these values:
200 x 300 = 60,000 pixels contained in the image.
How do 60,000 pixels lend a file size of 176K?
60,000 × 3 = 180,000
180,000 ÷ 1024 = 176

There are 3 bytes in a 24-bit color image. Multiply 3 bytes by 60,000 pixels, and the result is 180,000 pixels. Divide 180,000 pixels by 1024 bytes per kilobyte, and you get the file size value of 176K.

Remember: These are the basics that affect file size, but other factors contribute to size as well, such as layers and channels.

Resolution is usually measured in pixels per linear inch (ppi), although it can also be measured in pixels per millimeter. The image in my example has a resolution of 120 pixels per inch (ppi), or 14,400 pixels, which just happens to be 120 x 120, or 1202.

The dimensions of an image are its width and height when it is printed. To calculate these dimensions, all you have to do is divide the number of pixels by the image’s resolution:
200 ÷ 120 ppi = 1.667 inches (image width in print)
300 ÷ 120 ppi = 2.5 inches (image height in print)
Another way of calculating how much resolution an image requires is by multiplying the desired print size by the printer resolution. In other words, to print a 5-x-7-inch image at 300 dpi requires a resolution of 1500 x 2100 pixels per inch.

You’ll see recommended resolution settings somewhere between 72 ppi and 96 ppi even though resolution isn’t really a factor in preparing screen images. That’s just because monitors display somewhere in the 72 to 96 ppi range. So if you change the physical dimensions of an image, then it is always at a one to one ratio with the monitor. If you view an image whose resolution is higher than that of the monitor, the image appears larger on-screen than in its printed state. For example, try opening (or dragging and dropping) a 300 pixel-per-inch (ppi) JPEG file into a browser window. It explodes on your screen. Because the monitor can display only 72 to 96 ppi, it needs a ton of space to show all the pixels in the image.

Viewing Raster Images On-Screen in Photoshop

Resolution really doesn’t play a role in how you view images on-screen. The display of images on-screen is based on 1 image pixel per 1 screen pixel. The most important issue, then, is making sure that your image fits inside your (or your audience’s) monitor when viewed at 100%. This is where pixel dimensions come into play — especially if you’re putting images on the Web.

When you view an image on-screen, the display size is determined by the pixel dimension, plus the size and setting of the monitor. You therefore need to determine the demographics of your audience and then size your graphics accordingly.

A 17-inch monitor probably displays 1024 by 788 pixels. An 800 x 600 pixel image fills part of the screen. Change the monitor setting to 800 x 600, and the image fills the screen, with each pixel appearing larger.
On a 15-inch monitor, an 800 x 600 pixel image fills the screen. But a 1024 x 768 image can’t be viewed in its entirety.

You may also hear monitor resolution being referred to in graphic display standards, such as VGA (640 x 480 pixels), XGA (1024 x 768 pixels), UXGA (1600 x 1200), and so on.

Resolution is measured in pixels per inch, or ppi. You may also run across the term samples per inch (spi). Another term you will see often is dots per inch (dpi). Dots per inch is always used in reference to printers, scanners, imagesetters, and other paper-outputting devices. You may hear people refer to dpi as printer resolution.

Raster images in Photoshop

Raster images are usually the result of the digitizing of continuous-tone images, such as photographs or original painted or drawn artwork. Raster images are comprised of a grid of squares, which are called pixels. Pixel is short for PICture Element and is the smallest component of a digital image. If you’ve ever looked at a bathroom wall made up of those small square tiles reminiscent of the ’40s, you’re familiar with what a grid of pixels looks like: Each pixel lives in a specific location on that grid and contains a single color. When you edit a bitmap image, you are editing one or more pixels rather than an object-oriented shape.

Although it doesn’t seem like it when you’re viewing an image that fits inside your computer screen, your entire image can be broken down into a grid of square pixels. That means the elliptical shapes of my beanie also have to fit within this system of squares. But how do you fit a round peg in a square hole? By faking it. Unlike the true mathematical curve possible when drawing vector shapes, raster images must try to approximate a curve by mimicking the overall shape with square pixels.

Fortunately, the mimicry the pixels have to do is indecipherable with high-resolution images viewed at a reasonable distance. But when you zoom in, you can see that a curve in an image (like the curve of my beanie) is indeed comprised of square pixels. Raster graphics work great for photorealistic or painterly images where subtle gradations of color are necessary. On the downside, because they contain a fixed number of pixels, raster graphics can suffer a degradation of quality when they’re enlarged or otherwise transformed. They are also large in file size.

Bitmap images are resolution dependent. Because they contain a fixed number of pixels, the resolution of the device they are being printed to is only one of two factors that influence the quality of the image. The quality of the output also depends heavily on the resolution of the image. For example, an image with 72 dots per inch (dpi) doesn’t look any better printed on a 600 dpi printer than it does on a 1200 dpi printer. Likewise, a 300 dpi image doesn’t look as good printed on an old 72 dpi dot matrix printer as it does on a 1200 dpi printer.

Vector images in Photoshop

One cool thing about vector images, also called object-oriented images, is that when you zoom in on them, they don’t look blocky. That’s because vector images are comprised of segments — curved or straight — and anchor points — elements that indicate the endpoints of the segments — that are defined by mathematical objects called vectors. Vectors use a unique mathematical formula to define the specific location of an object as well as its geometric shape.

Vector images are usually the product of drawing programs, such as Adobe Illustrator, but Photoshop is also capable of producing a vector or two. And not to be outdone, its cousin Illustrator can also rasterize (or convert into pixels) vector artwork, thereby providing you with raster images to work with.

Here is some additional information about vector graphics:
-->A curve is still a curve, even at 20,000 feet. Because they are mathematically defined, vector graphics can be sized and otherwise transformed without an inkling of quality loss.
Take that little 2-inch spot illustration and size it up to mural size, and it appears identical.
A perfect true curve remains a perfect true curve, whether it’s 2 inches or 20 feet long.

-->You can get pretty pictures in small packages. Vector images can be small in file size because the file size depends on the complexity of the vector objects, not the size of the illustration.

Graphics that need clean lines, such as logos, typographic illustrations, and line art, work great in vector format.

-->Vector images are independent — resolution independent, that is. Not only can they be transformed and printed without a degradation in quality, but they also have no built-in resolution — they take on the resolution of the output device. For example, print my logo in Figure 1-1 to an imagesetter (a high-end printing device used for color separations) at 2400 dots per inch (dpi), and the image comes out at 2400 dpi. Print it to a 300 dpi laser printer and what do you get? A 300 dpi image. (If all this technical lingo like imagesetter and dpi is confusing.

Because your monitor can display images only on a grid, vector images display on-screen as pixels. This accounts for the jagged appearance you see when you zoom into a curved vector object. But don’t worry; it will print just fine.

Specifying Size and Resolution in Photoshop

Photoshop has evolved into a Swiss Army knife. Once only a pixel-based (or raster) application designed primarily for print, it has been transformed into a program capable of both vector- and pixel-based output with added features aimed at producing Web content as well.

You need to be aware of important issues when you produce both pixel-based and vector-based graphics. I give you a bit of background in that department in this chapter. Also, I show you the components that make up the physical aspect of your pixel-based image — the dimensions, the file size, and the resolution — and how they relate to one another.

Even though Photoshop can now produce vector graphics, its primary mission is to create awe-inspiring raster images. And because the issue of resolution is so critical to raster images, this chapter primarily discusses methods for sizing and resizing raster images.

You find out how to change any of the three components without harming your image. Yes, you can harm your image. Not intentionally, of course. But it can happen quicker than you can close a dialog box. But with a firm understanding of how pixels live and breathe, you can ensure that your images are safe from any undue damage.

Putting Images under the Microscope
Digital images fall into two camps, vector images, which are created based on mathematical formulas, and raster images, which are made up of pixels. Photoshop allows you to produce both types of images and even to combine both types within a single file.

Customizing Keyboard Shortcuts in Photoshop

For those of you who are like me — I avoid using a mouse and prefer the ease and speed of keyboard shortcuts — Photoshop now offers customizable keyboard shortcuts. You can assign shortcuts to menu commands, palette commands, and tools. You can edit, delete, or add to the Photoshop default set or create your own custom set. Here are the steps to work with keyboard shortcuts:

1. Choose Edit➪Keyboard Shortcuts.
For those who have good manual dexterity, you can also press Alt+Shift+Ctrl+K (Option+Shift+Ô+K).

2. Choose between the Photoshop Defaults set or create a new set by clicking the New Set button (the dogeared page icon) in the upper-right corner of the dialog box.
Clicking New Set makes a copy of the selected set for you to then edit and customize. If you choose a new set, name the set (leaving it with a .kys extension), and keep it stored in the Keyboard Shortcuts folder.

3. Choose Application Menus, Palette Menus, or Tools from the Shortcuts For drop-down list.

4. Select your desired command from the list. Type in the shortcut keys you want to assign to that command in the shortcut field. If you type a keyboard shortcut that is already assigned to that command, you can simply type over it.
As you well know, Photoshop often has multiple ways of accessing the same command. For example, you can create a new layer by using the Layers palette pop-up menu or buttons or by choosing the menu command Layer➪New➪Layer. Therefore, you may get a warning that your chosen command and another command on another menu must have the same shortcut and that changes will be applied to both If the keyboard shortcut you type is already being used, Photoshop warns you that if you accept the shortcut, it will be removed from the original command.

5. Click Accept or Undo. You can also click the Add Shortcut button.
If you later change your mind and want to use the original keyboard shortcut (if there was one), click Use Default. If you decide you don’t want the shortcut at all, click Delete Shortcut. And if you make a mistake, just click Undo.

Application and Palette menu commands must include a Ctrl (Ô on the Mac) and/or an F key in the keyboard shortcut.

6. When you finish, click the Save Set button (the disk icon).
If you want to delete the set, click the Delete Set button (the trash icon).

7. Click the Summarize button to save the keyboard shortcut set as an .htm file, which will load in your Internet browser. You can then print the file and keep it as a handy reference of your shortcuts.

8. Click OK to exit the dialog box.

Setting File Browser Preferences in Photoshop

Photoshop CS has added a new set of preferences for the File Browser. These preferences enable you to customize how the newly souped-up File Browser processes and displays your images.

Using the Preset Manager
Many of the palettes and tools Photoshop works with can use settings that you store on your hard drive as presets. For example, you can create custom colors and brush tips, build your own gradients, create a library of shapes, or compile a set of styles to apply to layers. You’ll want to become familiar with the Preset Manager, which provides a central management tool for all the options that are individually available from the palettes and tools themselves.

Just as with the tools, you can select, edit, and delete presets. The only thing you can’t do with the Preset Manager is actually create a preset. You must do this with the Tool Preset picker or Tool Presets palettes.

Here are some tips on using the Preset Manager:

-->To show the Preset Manager, choose Edit➪Preset Manager. To hide it, click Done.
-->To select a specific type of preset to work with, choose it from the Preset Type dropdown list.
-->To modify a preset, choose the option from the pop-up menu available in each preset’s dialog box. Click on the right pointing arrow to the left of the Done button to access the preset pop-up menu.
-->To load an existing set of presets from your hard drive, click the Load button and navigate to the presets you want to access. You can also choose a preset library listed under the pop-up menu of each preset type.
-->To store a new or modified group of settings, click the Save Set button and type a name.
-->To give a particular preset a new name, select the setting in the dialog box, click the Rename button, and type the new name.

You can rename multiple settings consecutively by clicking and Shift+clicking the items to be renamed and then clicking the Rename button. Photoshop asks you to supply a new name for each, in turn.

-->To quickly load the default preset library for any tool or palette, choose Reset [name] Preset from the Preset Manager pop-up menu. You can also replace your current Preset library with another.
-->Different preset display options are available on the Preset Manager pop-up menu.

Changing Memory and Cache Settings in Photoshop

The perennial question: How much memory does Photoshop require? The perennial answer: As much as you can cram into your computer! Memory is so inexpensive right now there’s no excuse for not having at least 512MB of RAM, and more is even better if you’re using an operating system that can handle extra memory efficiently, such as Windows XP and Mac OS X.

When you’ve crammed your RAM, you’ll want to make sure Photoshop can use as much as you can spare. You can use the Memory & Image Cache Preferences dialog box to allocate your memory.

Managing memory
Here’s how to allocate RAM:
1. Choose Edit➪Preferences➪Memory & Image Cache.
The Memory & Image Cache Preferences dialog box opens.
2. In the Memory Usage area, change the Maximum Used by Photoshop parameter.
Use a value of 50 to 80 percent, depending on how much memory you have to waste. Allocating more to
Photoshop reduces the RAM for other applications, so if you have other programs that need lots of memory, choose a prudent value.
3. Click OK to apply the option.
4. Exit Photoshop and relaunch the program to activate the new setting.

Setting aside memory for storing screen images
You can also set aside the amount of memory for storing screen images in the Memory & Image Cache dialog box, to speed up redraws of a reduced-view image on your screen as you make changes. You have two options. You can specify the number of copies of your image stored in memory, from the default value of 4 up to 8 levels. You can also set aside cache memory for drawing histograms (brightness graphs produced by the Levels command) if you use histograms frequently.

Plug-Ins and Scratch Disks in Photoshop

Plug-ins and scratch disks are a couple of unrelated options combined in a single dialog box. Briefly, plug-ins are mini software programs that add features to Photoshop. Scratch disks are free areas on your hard drive(s) that Photoshop uses as virtual memory when it is short on RAM. Read on to find out more.

Plug-ins
The Plug-Ins folder is where Photoshop stores all your filters and other plug-in add-ons. A default folder is created when you install Photoshop. Photoshop allows you to specify an additional folder to search other than its own Plug-Ins folder. This additional folder may come in handy if you want to keep your third-party add-ons separate from Photoshop’s native plug-ins. An auxiliary plug-ins directory (not nested within Photoshop’s own Plug-Ins folder) can simplify managing those extra filters, and you can turn off their use (potentially speeding up Photoshop’s load time) by deselecting the Additional Plug-Ins Folder check box in this dialog box. You can also use this option when you have some plug-ins installed for another application and want to share them with Photoshop without having to make extra copies in your Photoshop Plug-Ins directory.

To activate a new plug-ins directory, select the Additional Plug-Ins Folder check box and then click the Choose button. In the dialog box that appears, navigate to the folder you want to use and select it. Click OK. You then need to exit Photoshop and restart the program to activate the new directory.

If you have a plug-in or folder you’d like to deactivate, use a tilde (~) as the first character of the plug-in or folder name. Photoshop will ignore the plug-in(s) or folder(s) specified. Just remove the tilde from the name to activate the plug-in or folder. This can come in handy if you are having a program glitch and want to deactivate your plug-ins to troubleshoot whether or not they are causing the problem.

Scratch disks
Scratch disks are areas on your hard drive that Photoshop uses to substitute for physical RAM when you don’t have enough RAM to work with the images you have opened. Scratch disks are no replacement for physical memory, but there are many times when Photoshop will need them, even if you have huge amounts of memory.

Photoshop uses your startup drive (the drive used to boot your operating system) as its first scratch disk by default. That may not be the best choice because your startup drive is usually pretty busy handling requests of your operating system and, if you’re running Windows, requests for Windows’ own virtual memory scheme (your so-called swap file or paging file). Ideally, your scratch disk(s) should be a different hard drive and, preferably, the fastest one you have available.

If you have more than one hard drive, choose one other than your startup drive as your first scratch disk. Select your fastest drive; for example, select a FireWire (IEEE 1394) or USB 2.0 drive over one using the original, slow, USB 1.1 connection. If you have an Ultra-DMA EIDE drive or, better yet, a SCSI drive, use that. Although Ultra-DMA drives have transfer rates that rival even the speediest SCSI models, SCSI can be better because the SCSI bus is designed for multitasking. You’ll often get better performance than with an EIDE drive that shares one of the two EIDE channels with other devices.

If you don’t have a second hard drive, you can improve scratch disk performance by creating a partition on an existing drive for use as a scratch disk. Remember to keep the scratch disk defragmented (that is, with the files all organized together on your hard drive) by using your favorite defragmentation utility.

Adobe changed the format for serial numbers with Photoshop 7, and if you have old plugins that require a valid Photoshop serial number, you can enter the serial number from an older version into the space provided in this dialog box.

Setting up guides, grids, and slices in Photoshop

Guides are nonprinting lines you can create on your screen to make it easier to align objects.
Grids are vertical and horizontal lines in the background that make lining up objects even easier.
Slices are sections of an image you can create for Web page graphics so that each slice can be loaded and treated separately (usually in a table or similar arrangement).

In the Guides area, you can set these options:
-->Color: Either select a color from the drop-down list or click the color sample swatch to choose your own color. You may want to change the default color if that color is too similar to a dominant color in your image.

-->Style: Select from lines or dashed lines. If you work with images that contain many horizontal and vertical lines that extend across most of an image, dashed lines may be more visible.

In the Grid area, these are your options:
-->Color: Select a color from the drop-down list or click the color sample patch to define a specific hue.

-->Style: You can choose lines, dashed lines, or dots.

-->Gridline Every: Choose the distance between gridlines.

-->Subdivisions: Select the number of subdivisions for each gridline.

In the Slices area, these are your choices:
-->Line Color: From the drop-down list, choose a color for the lines that surround each slice.

-->Show Slice Numbers: If you select this check box, Photoshop adds a slice number to the display of slices, which makes it easier to keep track of individual slices.

Setting measurement preferences in Photoshop

In the Units & Rulers Preferences dialog box you can set the units used to measure things on-screen (inches, pixels, millimeters, and so forth) and to define a default column size when typing text in multiple columns. In addition, you can define the resolution of the image when you choose File➪New and select Default Photoshop Size from the Preset Sizes list.

In the Units area of the dialog box, you find these options:
-->Rulers: Select the measurement units Photoshop uses for rulers. Your choices are pixels, inches, centimeters, millimeters, points, picas, or percent. The most popular sizes are inches and millimeters, but if you’re working with publications and specifying in picas, you might prefer that increment instead. If you’re prepping Web graphics, you may prefer to have your rulers incremented in pixels.

-->Type: Choose the measurement used to represent the dimensions of type. Point size is almost universally used, but pixels and millimeters are also available. You may want to use pixels if you’re trying to fit type into a specific-sized area of an image.

In the Column Size area, you can specify the following:
-->Width: The width of the column in inches, centimeters, millimeters, points, or picas.

-->Gutter: The width of the area separating columns, also in inches, centimeters, millimeters, points, or picas.

In the New Document Preset Resolutions area, you can set the following:
-->Print Resolution: The default is 300 pixels per inch, a good setting to keep. You can change to another value and use pixels per centimeter as a measurement if you want.

-->Screen Resolution: Generally, 72 pixels per inch works with most images that will be prepped for screen viewing. You can select another resolution and use pixels per centimeter if you like.

Changing the resolution of an image after it’s been created can impact the sharpness of your image and degrade quality. It’s best to choose the final resolution you want when you create a document, whether you specify the resolution manually or use these presets.

In the Point/Pica Size area, you can choose whether you want to use a measurement of 72 points per inch (which first became relevant in the Macintosh realm and spread as desktop publishing became widespread) or the traditional 72.27 points per inch definition used in the precomputer era. Unless you have a special reason to choose otherwise, use the Postscript (72 points per inch) option.

Adjusting transparency and gamut in Photoshop

Photoshop uses colors and patterns to represent information about an image that is normally invisible, such as areas that are transparent, or parts of an image that contain colors that cannot be represented by your current display or printing system. The Transparency & Gamut Preferences dialog box enables you to tailor these displays to your own preferences.

For example, transparency is typically shown on the screen by using a gray-and-white checkerboard pattern. You can change the pattern and colors if you prefer another type of display.

Here is a rundown of the options you find in this dialog box:
-->Grid Size: You can choose small, medium, large, or no grid at all. You may want to switch from the default medium-sized grid to a large grid if you’re using a very high resolution setting (such as the 1920 x 1440 pixel setting I use on my monitor) so the grid is a little easier to see. (I don’t bother with this, myself.) Or you can switch to a smaller grid if you’re working at a 640 x 480 or an 800 x 600 resolution.

-->Grid Colors: The default light grid is the least obtrusive, but you can switch to a medium or dark grid if you want. Also, you are not limited to gray-and-white checkerboard squares. To choose custom colors, double-click the white and gray squares below the Grid Colors list.

-->Use Video Alpha: If you have a video board that supports chroma keying, select this option to be able to view video in the transparent portions behind a layer.

-->Gamut Warning: You can adjust the color used to represent out-of-gamut colors and to specify the transparency for the warning color. Double-click the Color box to set the hue and choose the transparency with the Opacity slider. The gamut warning is generally used before converting RGB images to CMYK to see which colors will be lost.

A gamut is the range of colors that can be displayed or printed. In Photoshop talk, out-of-gamut colors generally are those that can’t be represented by cyan, magenta, yellow, and black and, therefore, can’t be printed. To turn gamut warnings on or off, choose View➪Gamut Warning.

Adjusting your display and cursors in Photoshop

This Display & Cursors Preferences dialog box enables you to set several options that control how cursors display on-screen and three display parameters that may affect how quickly your computer completes an operation. The following list describes these options:

-->Color Channels in Color: When selected, this option tells Photoshop to show each of the color channels (for example, red, green, blue or cyan, magenta, yellow, and black) in their respective colors in the Channels palette. In most cases, you won’t want to use this feature. You need to be able to see the channels in their grayscale form to perform image-editing tasks such as converting from color to grayscale, channel masking, or for selective sharpening on certain channels.

-->Use Diffusion Dither: This option is a holdover from the days when those working with images sometimes used graphics cards and displays that could show only 256 different colors. With this feature active, Photoshop simulates all the colors in an image by creating mixtures of the 256 available colors in a pattern that the human eye automatically merges together. You can use this option to work with full-color, 24-bit images in 256-color viewing mode. However, any computer that meets the specs needed to run Photoshop should be able to operate in full-color display mode.

-->Use Pixel Doubling: Many dialog boxes and tools have preview windows that show the effect of the settings you’re working with. With this feature active, Photoshop doubles the size of the pixels in the preview only, reducing the resolution of the preview but speeding display.

-->Painting and Other Cursors: Choose the Standard option to show a tool’s cursor as an icon representing the tool itself (although I don’t know why you’d want to do this). Use Precise to switch to a cursor that has crosshairs, which is useful for positioning the center of a tool’s operational area in a particular place. Brush Size (available for painting tools only) tells Photoshop to show the cursor in the same size as the brush itself. Most users prefer to set the painting cursors to Brush Size and the other cursors to Precise. Some folks do complain that precise cursors are hard to see against some backgrounds, but you can always press the Caps Lock key to toggle precise cursors on or off.

Deciding how you want files handled in Photoshop

The options in the File Handling Preferences dialog box control how Photoshop handles files as they are opened and closed. Here’s the lowdown on these options:

-->Image Previews: Storing a preview thumbnail with an image can speed up browsing for the image you want. You can tell Photoshop to save a preview by default or to ask you first (in case you want to create images that are a little smaller in size, especially for the Web). Or you can also choose not to ever save a preview. Mac users need to select the kinds of image previews they need. Select the Icon option to enable an image icon to appear on the Desktop. Select the Macintosh Thumbnail option to see a preview in the Open dialog box. Select the Windows Thumbnail option to see a preview in a Windows OS. Finally, select the Full Size option to save a low-resolution version of the file to use in applications that can open only low-resolution (72 ppi) Photoshop images.

-->File Extension: You can select whether the file extensions appended to filenames (such as .psd, .tif, and so forth) are consistently uppercase or lowercase, as you prefer. On Macs, you can choose whether to add extensions by selecting from the Always, Never, or to Ask When Saving options. If you want cross-platform compatibility with PCs or prep Web graphics, select the Always option. Mac users, select the Use Lower Case option to save extensions as lowercase characters.

-->Ignore EXIF sRGB tag: When this option is selected, Photoshop ignores the sRGB tag that many digital cameras add to their EXIF (camera) data. The sRGB tag is widely used, but not well respected among many high-end digital photography professionals.

-->Ask Before Saving Layered TIFF Files: Photoshop can save an advanced type of TIFF file that includes layers, exactly as with its own native PSD files. However, many applications cannot read these files. If you always open TIFF files in Photoshop and don’t mind creating larger TIFF files in the process, you can disable this option. Otherwise, Photoshop asks you for confirmation each time you want to save a TIFF file that contains layers.

-->Enable Large Document Format (.psb): Photoshop can now create documents up to 300,000 x 300,000 pixels. You can save these humongous files as TIFFs (up to 4GB) or in the new .psb or Photoshop Raw formats, with no limitation in size.

-->Maximize PSD File Compatibility: Photoshop now lets you choose an option for file compatibility.

Not all applications can handle the more sophisticated features that may be stored in a PSD file (such as fancy layer effects). If you frequently open PSD files in applications other than later versions of Photoshop, you may want to set this option to Always. Keep in mind that you may lose some features when you do this. Choose Ask to have Photoshop prompt you when you save a file as to whether you want the option. Or select Never to ignore the option completely.

When you maximize compatibility, Photoshop saves a composite (flattened) version along with the layered file to ensure that older applications (such as Version 2) can read the files. However, this option also makes your file size balloon enormously. In addition, when you save in this mode, you get an annoying warning that your file may not be read by future versions of Photoshop. This silly warning appears every time you save a layered PSD file.

If you plan to use your PSD files in InDesign or Illustrator, you need to have the maximize compatibility feature turned on because those programs need to have a composite along with the layers.

-->Enable Version Cue: Select this option if your computer is located on a network and you need to share your files with others in your workgroup by using a server.

-->Recent File List Contains: Type a value from 0 to 30 to specify the number of recently used files you want displayed in the Recent File list on the File menu.

Setting Preferences in Photoshop Part 2

In the Options section of the General Preferences dialog box, you find nearly a dozen check boxes that you can select or deselect, as described in the following list:

-->Export Clipboard: When this feature is active, Photoshop transfers its private clipboard (used only within Photoshop) to the general Windows or Macintosh Clipboard so that you can paste information into other applications. If you activate this option, switching from Photoshop to other applications takes a little longer, and Photoshop’s clipboard contents replace whatever was in your system Clipboard when you switched.

The clipboard is generally a poor vehicle for moving image data between applications because the transferred information may not be of the best quality. Instead, save your file and open it in the other application. If you do this, you can turn off the Export Clipboard option, saving you some time when switching between applications.

-->Show Tool Tips: Photoshop can display little pop-up reminders about tools and other objects on your screen. If you find these reminders distracting, deselect this check box to turn off Tool Tips.
-->Zoom Resizes Windows: Select this check box if you want your document windows to grow and shrink to fit your document as you zoom in and out. Deselect this check box if you want the document’s window to always remain the same size; you might want to deselect the check box if you frequently work with several documents side by side and don’t want them to change relative size as you zoom in and out.
-->Auto-update Open Documents: When you’re working on an image and move to another application (such as ImageReady) to work on the same image, you’ll probably want the changes made in the other application to be reflected in the document still open in Photoshop. Select this check box so that Photoshop will monitor the document and update its version whenever the document is changed in the other application.
-->Show Asian Text Options: Although Photoshop supports Chinese, Japanese, and Korean text, this option is off by default. You can activate it here so that Asian text options become available as you work.
-->Beep When Done: I remember the bad old days when Photoshop would take a minute or two to apply the Gaussian Blur filter or perform calculations when merging even moderate-sized image layers. Photoshop wasn’t inefficient; computers a decade ago were really slow compared to those available today. The Beep When Done signal was my cue to stop watching television and resume working with Photoshop. Although most operations are a lot faster today, if you’re working with very large images or simply like to be notified when a step is finished, the beep option can be useful (or incredibly annoying to your coworkers).
-->Dynamic Color Sliders: The sliders in the Color palette change colors to match the settings you make. If your computer is on the slow side, you can turn off this feature to improve performance.
-->Save Palette Locations: Select this check box if you want Photoshop to restore your most recent palette locations the next time you start up. Deselect this check box if you always want your palettes in the same location each time you begin working.
-->Show Font Names in English: If you’ve selected the Show Asian Text Options check box, Photoshop can display font names in Chinese, Japanese, or Korean by turning this option off. Activate this option if you want font names displayed only in English, regardless of the other Asian text options you’re using.
-->Use Shift Key for Tool Switch: When this feature is active, you can change from one tool in the Tools palette to another in the same group (say, to change from the Gradient tool to the Paint Bucket tool) by pressing the Shift key and the keyboard shortcut for that tool.
-->Use Smart Quotes: Love ’em or hate ’em, you can instruct Photoshop whether to use smart (curly) quotes or plain (straight) quotes with this option.
-->History Log: You can have Photoshop record all your editing commands.

This feature is handy if you want to present a finished, fully edited image to a client or manager, but need to be able to show the steps of how you got there. Or maybe you want a record of the steps, so you can repeat them on other images and don’t want to rely on your memory.

You have a few formats in which you can save your edit history log:
-Metadata: Saving the log to metadata (information embedded in your image file) allows you to view the log in the File Browser window.
-Text File: You can save the log to a text file. Click the Choose button to provide a name and location for the file.
-Both: This option saves the log as both metadata and a text file.
-Edit Log Items: You choose Sessions Only, Concise, or Detailed. The Sessions Only option records your editing until you close the file or quit Photoshop. The Concise option keeps a comprehensive log (multiple sessions), but in short and sweet steps. The Detailed option provides a comprehensive, detailed log. For example, a concise log entry may be just Crop, whereas a detailed log entry may be Crop. To rectangle and then also provide the original and cropped dimensions, the angle and the resolution values.

-->Reset All Warning Dialogs: If you’ve turned off the display of certain warnings by selecting the Don’t Show Me This Dialog Box Again check box, you can reactivate all the warnings by clicking this button.

Setting Preferences in Photoshop Part 1

Photoshop stores settings for many different options in a Preferences file on your hard drive. The first time you run Photoshop after a new installation, you probably want to customize Preferences to suit your own needs.

You can access the Preferences dialog box by choosing Edit➪Preferences (Photoshop ➪ Preferences on the Mac). You can also press Ctrl+K (Ô+K on the Mac). The General Preferences dialog box (shown in Figure 6-1) pops up by default, but you can choose any of the other Preferences dialog boxes from the drop-down list. You can also move between the dialog boxes by clicking the Prev or Next buttons that appear in each of the Preferences dialog boxes. The next several sections give you a rundown of what you can do with the settings in the different Preferences dialog boxes.

When the General Preferences dialog box is visible, you can switch to the other Preferences dialog boxes by pressing Ctrl+1, Ctrl+2 (Ô+1, Ô+2 on the Mac), and so forth. These shortcuts can be useful if you need to frequently access particular dialog boxes.

Setting general preferences
The General Preferences dialog box is where you select some options that are, well, general in nature. You can select some choices from drop-down lists, and others are check boxes you can select or deselect to activate or disable that option. Here’s a rundown of options in the upper part of the dialog box:

-->Color Picker: Choose the familiar Adobe Color Picker to select precise colors or work with the Windows or Macintosh system color pickers, as desired. You might want to use the Windows color picker, for example, if you’ve previously defined some custom colors outside of Photoshop and now want to make them available for a Photoshop project.

-->Image Interpolation: When Photoshop resizes an image, it must either create new pixels (when making the image larger) or combine existing pixels (to make the image smaller). To do this, the program examines neighboring pixels and uses the information to derive the new or replacement pixels. You can select the type of mathematical algorithm Photoshop uses to do this. The Image Interpolation drop-down list offers these options:
-Nearest Neighbor (Faster): This is the fastest (and lowest quality) interpolation method, under which Photoshop examines only one pixel to perform its calculations. Use this method only if your work is not critical and your computer is relatively slow.
-Bilinear: This choice provides better quality and is almost as fast as Nearest Neighbor. With this method, Photoshop looks at pixels above, below, and on either side of the pixel being processed (four pixels in all).
-Bicubic (Better): This option is a new and improved version of the old Bicubic method. Most users will want to stick this option, which is the default setting. Photoshop takes a little longer to perform its calculations but generates an optimized pixel after looking at 8 surrounding pixels — one above, one below, two on the sides, and four in the corners.
-Bicubic Smoother: Like Bicubic, but provides the maximum amount of softening between pixel edges. A good method when upsampling, or enlarging, an image. Can slightly affect the sharpness of the resulting image.
-Bicubic Sharper: Again, like Bicubic, but applies just a little softening to pixel edges. This is a good method when downsampling, or reducing the size, of an image.

-->History States: Photoshop remembers how your document looks at various stages of editing, storing all the image information on your hard drive and listing the individual states in the History palette. Keeping track of every change you make requires lots of memory and hard drive space, so you can specify how many resources to use by typing a value into this box. The default is 20 (the max is 1000). If you have resources to burn and frequently find yourself stepping way back in time to modify or delete a step, you can type a larger number. If your resources are skimpy and you don’t anticipate making many changes to earlier steps (or are willing to take frequent snapshots or save interim images), you can enter a smaller number.

Customizing Workspace and Preferences in Photoshop

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To a certain extent, Photoshop lets you have it your way without having to make a trip down to the local burger shack. You can easily customize the look of your workspace, specifying everything from the location of palettes to the arrangement of dialog boxes when you begin a session.

You can even store these physical layouts and recall them anytime you like. Photoshop also makes it easy to choose how certain tools and features operate. You can choose how the cursors for tools such as brushes look, tell Photoshop your preferred way of storing files, and specify just how much memory you’d like to set aside for image editing. You can set all these preferences once and then forget them, or you can change them from time to time as your needs change.

Creating Workspace Presets
Photoshop is a complicated program; the more you learn the more complicated (and routine) your activities become. For one project, you may find yourself using the Styles palette repeatedly to add special effects to layers. For your next project, you may never use the Styles palette but require frequent access to the Paths palette to create curves that you use to make selections. And so it goes. Use custom presets to save time and effort, or to instantly clean up a messy desktop.

Custom workspaces come in handy if you share a computer with students, family members, or coworkers. Those who prepare images for both Web and print have different needs that may call for special workspaces, too.

You can create customized workspace presets that handle all these needs and a great deal more. Here are some of the ways you can tailor your workspace:

-->Combine palettes to group the ones you use most often together.
Drag a palette’s tab into another palette group to add it to that group. If the Layers, Channels, and History palettes are the ones you use most often, you might want to group them together. You can also hide palettes that you rarely use for a particular project, tuck them away in the Palette Well, or minimize them to their title bars.

Move a palette out of the way quickly by Shift+clicking its title bar. The bar snaps to the nearest screen edge.

Before saving your workspace preset, show or hide the palettes as you prefer them and move them to the locations you want on your screen.

-->Position dialog boxes.
Photoshop’s menu bar dialog boxes pop up in the same location they appeared the last time you used them. You may want to drag them to a specific place on your screen and store that location when you save your workspace preset. When I’m working with a large image, I sometimes position dialog boxes on the screen of my second monitor to maximize the area for the image on my main display.

-->Customize the Options bar.
You can grab the gripper bar at the left edge of the Options bar and drag it to another location. For example, you can dock the bar at the lower edge of your screen or have it float in a specific place on your Photoshop desktop. You can also double-click the title bar of the floating Options bar to collapse it so that only the active tool’s icon is showing. Photoshop stores these settings with your workspace preset.

Saving and Deleting Presets
After you’ve set up your workspace, you can save it by choosing Window➪Workspace➪Save Workspace. In the Save Workspace dialog box that appears, type a name for your saved workspace and click the Save button. Your saved workspace now appears as a listing on the Workspace submenu.

To delete a saved workspace, choose Window➪Workspace➪Delete Workspace. In the Delete Workspace dialog box that appears, choose the name of the workspace you want to remove from the drop-down list. Click the Delete button, and your preset is gone, gone, gone.