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.