Batch Processing Actions in Photoshop

Photoshop’s Batch feature lets you apply an action to a group of files. Suppose you want to make changes to a series of files. You could open each file in Photoshop, play the desired macro, and then save the file. But that might take a few minutes, or much longer if you have a lot of files to process. If you want to keep your original file, too, you have to remember to save each file in a new folder. Batch processing can automate tedious chores like this for you.

To check out this useful tool, copy some files (at least five or six) to a new folder and follow these steps:

1. Make sure that all the files are in a single folder of their own.
Photoshop by default works on all the files in a folder. You have to use the File Browser if you want to choose only some of them using the Batch feature.

2. Choose File➪Automate➪Batch.

3. From the Set pop-up menu, choose the set that contains the action you want to apply.
If you have only one set of Actions loaded, it appears by default.

4. Choose the action you want to apply from the Action pop-up menu.

5. From the Source pop-up menu, choose Folder.
You can also select Opened Files to process files you already opened in Photoshop; Import to process a series of files captured with your scanner or transferred from your digital camera; or File Browser to process files you selected in the File Browser. File Browser is a good method for processing files that do not appear in the same folder.

6. Click the Choose button, navigate to the folder you want to use, and click OK (in Windows) or Choose (in Mac OS).

7. Select other options in the Source area, as desired. Here’s a description of your choices:

-->Override Action “Open” Commands: Normally, Photoshop automatically opens each of the files in the selected folder and processes them, so your action doesn’t need to contain an Open command. However, if the macro does contain an Open command, you’ll want to select this option to tell Photoshop to substitute files in the selected folder rather than those that might be specified in your action’s own Open command.

Don’t select the Override Action “Open” Commands option if you do want Photoshop to use files specified by the action. For example, your action might open a file and copy its contents to the file being batch processed. In that case, you would not want to override the macro’s Open commands.

-->Include All Subfolders: Select this option to process files in subfolders within the folder specified.

-->Suppress File Open Options Dialogs: Select this option to have Photoshop disregard any options that could be possibly selected upon opening a file. Suppress File Open Options Dialogs is a new option in Photoshop CS.

-->Suppress Color Profile Warnings: When Photoshop opens a file that contains its own color profile, it asks whether you want to use that profile or Photoshop’s default profile. Selecting this check box suppresses that choice; Photoshop always uses its own default color profile.

8. In the Destination area, tell Photoshop what to do with each file after it is processed with the macro.
Choose one of the following options from the drop-down list:
-->None: Leaves the file open on your Photoshop desktop without saving it (unless the action itself contains a Save command).

-->Save and Close: Closes the files in the same folder where Photoshop found them. Your original file is overwritten, so use this option only when you don’t want to save the original or have another copy.

-->Folder: Saves the document in a folder.

9. If you chose Folder in Step 8, click the Choose button and navigate to a destination folder for your files.

10. Select the Override Action “Save As” Commands check box to ignore any Save As parameters in the action and use the filenames of the files as specified in the File Naming section described in Step 11.

11. In the File Naming section, specify how you want Photoshop to create the filenames for the new, processed files by choosing from the pop-up menus.
You can choose options from six popup menus, depending on how long and complicated you want the filenames to be. Here are a few suggestions:

-->You’ll usually want to choose Document Name from the first popup menu. If you do that, Photoshop retains the document name of the original file. If your documents are named Sunset.tif, Sunrise.tif, and Winter.tif, for example, the processed versions are given exactly the same names.

There are other choices in the popup menus, such as consecutive serial numbers or mm/dd/yy choices, which you can apply if you want. The serial numbers choices create consecutive numbers, either 1-, 2-, 3-, or 4-digit numbers, as well as serial letters, such as a, b, c or A, B, C, for each file created.

-->You’ll usually stick with the file’s extension in the second pop-up menu. Choose extension to apply a lowercase version of the file’s original extension, or EXTENSION to apply an uppercase version.

-->Use the four additional pop-up menus if you want to create longer and more complicated filenames.
For example, if you choose Document Name in the first pop-up menu, 4 Digit Serial Number in the second pop-up menu, ddmmyy in the third pop-up menu, and extension in the fourth pop-up menu (as shown in Figure 6-6), the Sunset.tif, Sunrise.tif, and Winter.tif files are renamed Sunset0001120302.tif, Sunrise0002120302.tif, and Winter0003120302.tif if they’re saved on December 3, 2002.

When processing large numbers of files, these naming tools can help you keep track of when and how the files were created.

12. Select the Windows, Mac OS, or Unix check box to specify what operating system you want the saved filenames to be most compatible with.

13. From the Errors pop-up menu, choose whether you want Photoshop to stop processing a batch when it encounters an error or whether you want it to simply continue and list the errors in a file. If you choose the latter option, click the Save As button to specify a log file and location for the log.

If you want to apply several different actions to a single set of files, or to apply the same action to multiple folders of files, just create an action that includes multiple batch-processing directives. To process multiple folders, you can also deposit shortcuts (in Windows) or aliases (in Mac OS) to each of the additional folders in the main source folder, and then select the Include All Subfolders check box in the Source area.

14. When you’re done selecting options in the dialog box, click OK to start the batch processing.

Saving actions in Photoshop

If you create your own sets of actions, you may want to include them in custom sets that you can load or remove as needed. Just follow these steps:

1. Display the Actions palette in List mode.
2. Click the Create New Set button in the Actions palette or choose New Set from the palette pop-up menu.
The New Set dialog box appears.
3. Enter a name for your actions set.
4. Drag any existing actions you want to include from their locations in the Actions palette to a new location within your new set folder.
5. Create any new actions you want to include within the new set.
6. Select the name of the set and choose Save Actions from the palette pop-up menu.
7. Save the set in the Photoshop Actions folder or another folder of your choice.

Editing an action in Photoshop

You can also edit individual steps of an action. Here are some of the editing changes you can make:
-->Move a step: To move a step from one place in the action to another, click the action you want to relocate and drag it to its new place in the action list.

-->Add a step in the middle: To add a new step in the middle of an existing action, select the step that you want to precede the new step. Click the Record button and perform the steps you want to add. Click the Stop Recording button when you’re finished.

-->Add a step to the end: To add a new step at the end of an existing action, select the name of the action, click the Record button, and perform the steps you want to add. Click the Stop Recording button when you’re finished.

-->Remove a step: Click the step you want to delete and either drag the step to the trash can icon, or click the trash can icon and click OK in the dialog box that pops up. (Hold down the Alt key [Option key on the Mac] to bypass the dialog box and delete the step without confirmation.) You can also select a step and choose Delete from the palette pop-up menu.

-->Duplicate a step: Hold down the Alt key (Option key on the Mac) and drag the step you want to duplicate to another location in the Actions palette. Photoshop then creates a copy of the step, leaving the original step where it was. You can also select a step and choose Duplicate from the palette pop-up menu or click the Create New Action button in the Actions palette. Photoshop then creates a duplicate step immediately after the one being copied. You can then drag the duplicate to the position where you want it to appear. You can also drag a step onto the Create New Action button to duplicate the step.

You can remove or duplicate an entire action by using the procedures described in the preceding list for removing a step and duplicating a step.

Editing and Managing Actions in Photoshop

The first thing you need to do after you create a new action is to try it out by opening an image and clicking the Play button in the Actions palette. If the action doesn’t perform as you expect, you may need to edit your action to fine-tune it. You also may need to edit an action to add features or change the action’s behavior in some way. For example, you might decide that you want your resizing action to change the size to 45 percent rather than 50 percent. Photoshop enables you to edit your actions fairly easily.

You have a lot of editing options; you can change the action’s name, keyboard shortcut, or color-coding of an action. That’s easy enough: Just double-click the action name in the Actions palette to enter a new name, or select the action, choose Action Options from the palette popup menu, and change the information as desired. You can also hold down the Alt key (Option key on the Mac) and click the action’s name in the Actions palette to open the Actions Options dialog box.

Re-recording an action
As easy as editing an action is, often your best option is to simply re-record the action from scratch. If the action is not long or complex, you can often re-record it in less time then editing the existing action takes.

You can re-record an action two ways:
-->Create a new action from scratch: Perform all the steps again to replace the old action with a new one, saving the action under the same (or a different) filename.

-->Use the clever Record Again feature: Photoshop runs through the steps you already recorded, opening the appropriate dialog boxes used the first time around so you can enter new values.

This method is very handy if you just want to change some of the parameters but keep the steps the same and in the same order. You don’t even have to remember what steps you used. Photoshop runs through them for you as you record the steps, or macro, again.

To re-record a macro with the Record Again option, select the name of the macro you want to re-record and choose Record Again from the palette pop-up menu. As the different dialog boxes appear, enter the values you want and click OK until the macro is finished.

Slowing down action playback

When you play back an action to test it, the action may run too quickly for you to see exactly what is going on. To slow things down, choose Playback Options from the palette pop-up menu and choose a playback speed in the Playback Options dialog box.

Select Accelerated to zip through an action at normal speed; Step by Step to command Photoshop to stop between actions so you can examine what has happened, or Pause For to create a short pause before moving on. If you want to get really fancy, you can select the Pause for Audio Annotation check box and use your microphone to describe what each step does.

Creating a New Action in Photoshop

The hardest part about creating a new action is figuring out what functions you want to automate.
Think about steps that you carry out over and over, and whether you could be more productive if you had an action that could do them for you. Then, examine the actual steps you want to automate so that you can record them. After that, creating a new action involves little more than starting Photoshop’s macro recorder and carrying out the steps you want to include in the action. You might want to create your own action to reduce images to a constant 500 pixels wide for display in an eBay auction, for example. Or you might want to save a bunch of files in a particular format or convert them from RGB color to grayscale.

Here are the steps to follow to create a new action:

1. Open an image.
2. Display the Actions palette in List mode.
3. Click the Create New Action button at the bottom of the Actions palette.
You can also choose New Action from the palette pop-up menu.
The New Action dialog box opens.
4. In the Name text box, enter a name for the action.
5. From the Set pop-up menu, choose the actions set. If you have more than one actions set open, choose the actions set in which you want to place the new action.
You may want to associate the action with a button on the keyboard.
Function keys like F2, F3, and so on are very useful for actions you perform all the time.
6. To associate the action with a function key shortcut, choose the name of the function key from the Function Key drop-down list.
Select the Shift or Control (Ô on the Mac) check box to use either of these keys along with the function key.

Any keyboard shortcut you assign to an action overrides the default function already assigned to the keyboard shortcut. You can revert to the original shortcut by choosing Edit➪Keyboard Shortcuts.

7. From the Color drop-down list, select a color to mark your action in Button mode.
This option enables you to group related actions by color.
8. Click the Record button in the New Action dialog box to begin recording.
9. Carry out all the steps you want to record.
10. Click the Stop Playing/Recording button at the bottom of the Actions palette to finish the action.
Your new action appears in the Actions palette in both List and Button modes.

Playing a preset action in Photoshop

To play a preset action, just open the file you want to apply the action to and then do one of the following:

-->In List mode, select the action you want to play, or expand the action and select the step you want to begin with. Then click the Play Selection button at the bottom of the Actions palette. You can also choose Play from the palette pop-up menu.

-->In Button mode, click the action you want to play. There are no other options.

If you want to play back just one step of an action, say, for testing purposes, select the step you want to play in List mode and then Ctrl+click (Ô+click on the Mac) the Play button in the Actions palette. You can also simply double-click the step in the list while holding down the Ctrl key (the Ô key on the Mac).

Introducing Preset Actions in Photoshop

Photoshop’s preset actions are located in a series of files in the Actions folder. The default actions are loaded by, um, default, when you first open Photoshop. However, other preset actions are available for you to open and use. They include Frames (for putting frames around your images), Text Effects (for enhancing your text), and Textures, for adding textures to your selections.

Preset action options
Here are some other tidbits about using preset actions :
-->If you saved actions of your own (as described later in this chapter) somewhere other than the Photoshop Actions folder, you can navigate to that folder by using the usual file navigation commands.

-->To remove the existing actions and replace them with the set you are loading, choose Replace Actions from the palette pop-up menu.

-->To reset the Actions palette to the Default Actions set (removing all other sets you may have loaded), choose Reset Actions from the palette pop-up menu.

-->To clear all actions from the Actions palette, choose Clear Actions from the palette pop-up menu. (You might want to do this when creating your own set of actions from scratch.)

-->To rename an action set, select it and choose Set Options from the palette pop-up menu.

Loading preset actions
Follow these steps to load preset actions.

1. In the Actions palette, click the palette pop-up menu arrow and choose Load Actions.
Photoshop opens the Photoshop Actions folder in the Load dialog box. This folder contains several sets of actions presets.

2. Select one of the actions sets.

3. Click the Load button.

Photoshop’s additional actions presets also appear at the bottom of the Actions palette pop-up menu. You can add any of them to your current set by clicking the set’s name. Any action sets that you create yourself (as described later in this chapter) also appear in the pop-up menu if you save them in the Photoshop Actions folder.

The new actions presets appear in the Actions palette, appended after the default actions that are already there. You can show or hide the actions in the Default Actions or Image Effects sets by clicking the expand/collapse arrow in the third column.

You can also make actions available or unavailable for an entire set by clicking the first column in the Actions palette next to the action set’s folder icon.

Examining an Action in List Mode in Photoshop

Try this quick practice run to see exactly how the Actions palette works:

1. Display the Actions palette in List mode.
If you’re in Button mode, click the palette pop-up menu arrow and select Button mode to untoggle the option. You need to be in List mode to create an action.

2. Expand the Default Actions folder, and click the right-pointing arrow next to the name of the action.

3. Click the right-pointing arrow next to the step you want to change.
The step expands to show the parameters used for that step. For example, for the Vignette (Selection), the layer is filled by using white at an opacity of 100 percent and by using the Normal fill mode.

4. You can click in the dialog box column for several of the steps (Make Snapshot, Feather, Make Layer, and Fill). You can select or deselect this column for a specific step to control whether the dialog box for that step is displayed.
For example, with the Vignette (Selection) action, if you deselect all the boxes in the dialog box column except for the one next to Fill, the action proceeds without input from you until it reaches the Fill step. Then the Fill dialog box pops up, and you can change settings such as the fill color, opacity, and fill mode. You can also click in the dialog box column next to the action’s name to turn on or off all the marked dialog box steps in the macro.

Getting to know List mode in Photoshop

When you’re working in List mode, the Actions palette has these three columns:
-->The leftmost column contains check boxes that you can select or deselect to control what actions are available in Button mode. You can use this column to ensure that your most commonly used actions are available for use in Button mode and those that you don’t use very often are hidden.

-->The second column toggles on or off the display of dialog boxes in actions. Some actions include options you can select while running the macro. For example, the Vignette (Selection) action, which creates a faded frame around a selection, includes a dialog box that lets you specify the width of the fading. This dialog box is shown only when you select the dialog box column; if you deselect that option, the action uses a default value of 5 pixels as the width for the feathered effect.

-->The third and widest column shows the name of the action. Click the right-pointing arrow to the left of the action’s name to reveal the individual steps of the action. Many (but not necessarily all) steps have their own arrows, which can expand or collapse to show or hide the options used to carry out that step. In case you’re curious, the good folks at Adobe call these twisty-turny arrows disclosure triangles.

At the bottom of the Actions palette in List mode, you find six icons, not all of which are available at all times. The following list describes the icons from left to right:

-->Stop Playing/Recording: This icon is active when you’re recording a macro. Click it to stop recording (or to stop playing back an action).

-->Begin Recording: Click this icon to begin recording a macro.

-->Play Selection: Click this icon to begin playing a selected action. Playback begins at the step selected; you can choose the action’s name to start the macro at the beginning, or expand the macro and select any step to begin playback at that point.

-->Create New Set: Click this icon to create a new action set.

-->Create New Action: Click this icon to begin a new action.

-->Delete: Click this icon to remove a selection action or step.

You can also find all these commands on the Actions palette pop-up menu.

Creating Actions for Productivity and Fun in Photoshop

Practice makes perfect, but when it comes to repeating the same steps in Photoshop over and over, the result is often tedium and impatience. You wouldn’t want to have to reinvent the wheel each time you wanted to go for a spin around the block, so why repeat the labor needed to carry out specific tasks if you don’t have to? Photoshop lets you record steps by using a fast and fun feature called Actions.

Photoshop actions are similar to the macro recording features found in your word processing or spreadsheet program, but they’re usually easier to create and have capabilities custom-tailored for image editing and customization.

For example, Photoshop has preset actions to create a wood frame, simulate water reflections, or provide a molten lead look. You can also use preset actions to create filterlike effects. And then there are the chores you can automate on your own.

Using the Actions Palette
Not surprisingly, a palette is dedicated to the automation of various chores. To view the Actions palette, choose Window➪Actions (or press F9), or click the Actions tab in its palette group or in the Palette Well. You can view the Actions palette in two different modes, each of which is useful in its own way.

Here’s a short description of each mode:
-->List mode: List mode is the default display in which each action is shown as a folderlike heading. You can open the heading to reveal all the steps within the action or collapse the heading to hide them. You operate in List mode when you record an action and when you edit individual steps. List mode also lets you perform only some of the steps in a macro.

-->Button mode: Button mode, shown in Figure 6-2, is a convenient, compact mode that hides all the inner workings of the actions, presenting only a button face that you can click to trigger a particular macro. Button mode is fast and easy; just click and go.

Importing and Exporting PDF Files with Annotations in Photoshop

You can view PDF or FDF (Forms Data Format) documents that contain annotations, review the annotations, and make new notes of your own. If you want to send an image file to a friend or colleague who doesn’t have Photoshop, you can still get input. You can even include notes of your own. To export your file (and its annotations) for review in Adobe Acrobat, just save the document and choose PDF as the format. Then when your Acrobat-using friend sends the file back to you, just follow these steps to access his or her input:

1. Choose File➪Import➪Annotations.
2. Navigate to the PDF or FDF file you want to open.
3. Click the Load button.
Photoshop imports the file with the annotations intact.

Creating an Audio Note in Photoshop

If you have a microphone connected to your computer, you can add audio notes to your image files. Audio notes are great for adding annotations that take a long time to type or that are better explained through audio.

Audio annotations can bloat your file size, so unless using audio annotations is really more advantageous, stick with text notes.

To add an audio message to your file, just follow these steps:
1. Select the Audio Annotation tool.
Press N to activate the Notes tool and then Shift+N to choose the Audio Annotation tool.
2. If necessary, change the author name or note color in the Options bar.
3. Click in the image where you’d like to include the audio annotation.
4. Click the Start button (Windows) or Record button (Mac OS) and begin speaking into the microphone.
5. Click Stop when you’re finished talking.
To play the audio annotation, doubleclick its icon.

Creating a Text Annotation in Photoshop

To create a text annotation, follow these steps:
1. Select the Notes tool in the Tool palette (or just press N).
2. If necessary, change the name in the Author text box in the Options bar.
Just double-click inside the Author text box and start typing.
By default, when you create a note, the name you entered when you installed Photoshop appears as the author of the note. However, you may be working on an image with someone else’s computer, or you may be on the lam and using an assumed name.

Be sure that everyone looking at the file uses a unique name so that you can sort out the various notes and, perhaps, give all of them their proper weight (that is, always do what the boss says, but take Seymour the intern’s comments with a grain of salt).

3. From the Font and Size drop-down lists in the Options bar, choose a font and font size for the text.
Selecting a particular font and size for each author may just be a matter of preference or readability or can be used to further differentiate between authors’ comments. You choose font sizes in relative sizes from Smallest to Medium to Largest so Photoshop can adjust the notes to be readable on monitors set for different resolutions.
4. Click the Color box on the Options bar and select a color for the title bar of each note and the color of its icon when you minimize the note.
Color-coding is a good way to differentiate authors, as well as priorities. For example, you can use Red, Yellow, and Green to indicate relative status of a particular suggestion, or select a color to represent a particular author.
5. Click in the note’s window and type the text you want to enter.

You can use traditional editing commands, such as the Backspace key, Ctrl+X, Ctrl+C, and Ctrl+V (Ô+X, Ô+C, and Ô+V on the Mac) to edit the text.

6. When you’re finished entering a note, click the note’s Close box on the right end of the title bar (Windows) or the left end of the title bar (Mac OS).
Photoshop minimizes the note to an icon.

Having Your Say with Notes and Audio Annotations in Photoshop

Text annotations (which Photoshop calls notes) are text comments that appear as icons within an image document when you choose to make them visible. If you’re reviewing someone else’s notes, you simply doubleclick the note to view it or to modify the text it contains.

You can do lots of things with notes:
-->Show or hide all the notes: Choose View➪Show➪Annotations.
-->Expand any note from its icon: Double-click the icon.
-->Edit a note: Expand the note and revise the text by using standard editing commands.
-->Delete a note: Select the note and press Delete.
-->Remove all closed notes: Right-click any note (Ctrl+click on the Mac) and choose Delete All Annotations from the context menu that pops up. You can also select a note and click Clear All in the Options bar. This removes all closed notes but doesn’t remove notes that are open.
-->Move a note’s icon: Drag the icon. (The note still pops up in its original location, however.)
-->Relocate a note’s window: Open the note and drag its title bar to the new location. It then pops up in the new location.

Applying Annotations and Notes in Photoshop

Everybody’s a critic! That’s especially true when you’re using Photoshop in a work environment — or in any scenario that involves anything but 100 percent freedom to perform your Photoshop magic as you want. Sometimes, you’ll want to collect comments from your colleagues, approvals from your supervisors, ideas from your friends, or nit-picks from your clients. Photoshop lets everyone have his or her say by using annotations, notes, or audio comments.

You can use these clever feedback tools without worrying about physically modifying the work that you’ve carefully done. Imagine sticky notes you can move around your screen, and you’ll see what Photoshop’s Annotations feature can do for you. Text documents often are distributed for approval in a Portable Document Format (PDF) format by using Adobe Acrobat Reader, and comments are added by using the full Acrobat application.

Photoshop is compatible with Acrobat, too, so you can save your Photoshop files in the PDF format. For more detailed information on the PDF format, see Adobe Acrobat 6 PDF Bible, by Ted Padova (published by Wiley Publishing, Inc.).

Using the Art History Brush Tool in Photoshop

The Art History Brush tool is an interesting variation on the plain old History Brush tool. Both paint over an image by using information from a previous state. The Art History Brush tool, however, includes several choices in the Options bar that let you apply brush-stroke effects to your image as you paint:

-->Style: The Style menu contains various-shaped brush stroke styles, such as Tight Short, Loose Medium, Dab, or Loose Curl. Although their names describe the look of the strokes fairly well, you’ll want to experiment with them to see exactly what they look like.

-->Area: This option controls the area covered by the paint stroke independently of the brush size you select. The larger the size, the more area that’s covered, and the more brush strokes that are applied per movement.

-->Tolerance: This option adjusts the amount of the change applied to your image. A low tolerance value lets you apply strokes anywhere in the image, regardless of color values. A high tolerance limits Art History strokes only to areas that are very different from the source state or snapshot, thereby making your image not quite as dramatically different from the original.

The result of using these options is an interesting hand-painted effect that you can control quite easily after you’ve had some practice. The Art History Brush tool often works best when you use a state that is quite different from the state you’re painting over. For example, you can apply a heavy filter that makes the image almost unrecognizable and then use that filtered image to paint with the Art History Brush tool. You can even completely fill an image with color or texture and work with that. To paint with the Art History Brush tool, follow these steps:

1. Apply any effects you want to use to a chosen state.
2. Click in the far-left column in the History palette to select the state you want to use as the source for the Art History Brush tool.
3. Select the Art History Brush tool from the Tool palette.
You can also press Y or Shift+Y to select it.
4. Select from the choices in the Options bar.
Several of the options, such as Brush, Mode, or Opacity, are similar to the options available with the ordinary Brush tool. The new options are Style, Area, and Tolerance.
5. Paint with the brush to get the effect you want.
Don’t forget that you can use the History palette to reverse Art History strokes that you change your mind about!

Using the Fill to History Feature in Photoshop

If you can easily select the area you want to replace with a specific state, you can use the Fill to History feature. Suppose you didn’t like the sky in a particular image. You selected the sky area and then added clouds by using the Clouds filter. Now you want to put the original sky back, but don’t want to reverse any of the other edits you performed in the meantime. Just follow these steps to replace an area by using the Fill to History feature:

1. Select a state as the source for the Fill to History function in the History palette.
For example, select the state that has the original sky.

2. Choose the current state and use your favorite selection tools to select the area you want to replace.
For example, if you remembered to save your original sky selection when you originally added clouds, you can choose Select➪Load Selection and retrieve that selection.

3. Choose Edit➪Fill and then select History from the Use pop-up menu.

4. Click OK to fill your selection with the image area from the selected state.

When Photoshop won’t let you go back
Sometimes you may see a No symbol when trying to use the Eraser with the Erase to History option, the History Brush tool, or the Fill with History command. You must be sure that your current image is the same file size (same number of pixels) as the state you are trying to go back to. Actions such as cropping, trimming, using the Image Size or Canvas Size commands, or rotating any amount other that 180 degrees can prevent you from going back to a previous state. However, if you happen to have a square image, you can rotate in 90-degree increments and still use the Eraser with the Erase to History option.

Using the History Brush Tool in Photoshop

You can also use the History Brush tool to apply an image area from a different state or snapshot to your current state. You’d want to use this tool to restore a portion of an image to an earlier state, while leaving the rest of the heavily modified image alone. Just follow these steps:

1. In the History palette, click in the far-left column of the state or snapshot you want to use as the source for the History Brush tool.
An icon appears, indicating that Photoshop will use this state as the source for the History Brush tool.
In my example, I chose my original image just after cropping it.

2. Select the History Brush tool in the Tool palette.
You can also press Y or Shift+Y to select the tool.

3. On the Options bar, choose any other brush options you want to use, such as brush size and type, mode, opacity and flow percentages, and airbrush.
Having access to blend modes is one advantage the History Brush tool has over the Eraser tool and the Erase to History option.

4. Select the layer in the Layers palette and select the state that you want to paint on in the History palette.

5. Begin to paint.
Photoshop paints over the image in the layer with the image from the state you specified as the origin for the History Brush tool. I painted my original over my filtered image. (I used the Graphic Pen filter.)

Restoring Part of an Image in Photoshop

Although the concept may seem like quantum physics, you can erase and brush on an image by using previously saved states or snapshots. What? Okay, let me try this again. You can erase portions of an image to a history state, as well as paint on an image from a history state. This means that traveling through time doesn’t have to be an all-or-nothing thing; you can erase or paint portions of a different state onto your currently active state.

For example, suppose you applied a blur filter to a face and decide later you want to make the eyes sharp again. You can use the Eraser tool with the Erase to History option, or the History Brush tool, to paint over the eyes with information from an earlier state before you blurred them.

Using the Eraser with the Erase to History option
You’d want to use the Eraser with the Erase to History option when a portion of an earlier state or snapshot contains information that you want to include in an image that has otherwise been extensively edited. To erase and restore to a portion of an earlier state or snapshot, just follow these steps:

1. In the History palette, click in the 4 far-left column of the state or snapshot you want to use as the source for the Eraser tool with the Erase to History option.
An icon appears, indicating that Photoshop will use this state as the source for the Eraser tool with the
Erase to History option.
2. Select the Eraser tool.
3. Choose the Erase to History option in the Options bar.
4. Choose any other Eraser tool options you want to use, such as brush size and type, blend mode, opacity and flow percentages, or airbrush.
5. Select the layer and state you want to erase.
6. Begin to erase.
Photoshop removes the image in the layer and replaces it with the image in the state you specified as the origin for the Eraser with the Erase to History option. You can convert the Eraser tool temporarily to use the Erase to History option by holding down the Alt key (Option key on the Mac) when you erase or paint.

Taking Snapshots in Photoshop

Snapshots are duplicates of your image at a particular point in time, similar to saving a document under an alternate name. (Photoshop automatically names the snapshots something generic like Snapshot 1 or Snapshot 2.) However, snapshots are temporary copies, available only during your current work session. When you save your image and close it, you lose all the snapshots. So thinking of snapshots as a way of saving your history lists at various points in time while you’re working is best.

Snapshots are a handy way to alternate between versions of an image when you’re making major changes. For example, if you plan to apply several filters that will drastically modify your image, you may want to save a snapshot before you use the filters and save another one after you’ve applied them. You can then click either snapshot to switch from one version to the other quickly. The second you close a file, the snapshots you’ve taken disappear forever.

To take a snapshot, follow these steps:

1. Select the state at which you want to take a snapshot.
The state can be the most recent one with all your latest editing changes, or an earlier state.

2. Choose New Snapshot from the palette pop-up menu.
Or right-click (Control+click on the Mac) the state and choose New Snapshot from the context-sensitive menu. The New Snapshot dialog box opens. If you want to bypass this dialog box, just click the New Snapshot button to create a snapshot. Photoshop names your first snapshot Snapshot 1.

3. In the Name box, enter a name for the snapshot, preferably one that helps you remember the contents of that particular snapshot.
You can add or change the name of the snapshot later by double-clicking the snapshot name in the history list.

4. Choose one of the subtypes of snapshots in the From menu:
-->Full Document creates a snapshot of all the layers in the image at the currently selected state. (This is the default.)
-->Merged Layers creates a snapshot with a single layer, merging all the layers in the image at the currently selected state. Use this option to create a flattened version with the visible layers combined.
-->Current Layer creates a snapshot of only the active layer of the current state.

5. Click OK to create the snapshot.
If you no longer need a snapshot, select the snapshot and press the Delete key. You can also click the trash icon, or drag the snapshot to the trash icon, or choose Delete from the palette options menu.

Navigating the history list in Photoshop

You can move up and down the history list even if the list isn’t visible on your screen. The Edit➪Step Forward and Edit➪Step Backward commands move forward and back in the history list. The best way to access these commands is to use the keyboard shortcuts:

-->Press Alt+Ctrl+Z (Option+Ô+Z on the Mac) to move backward in time (upward in the history list).

-->Press Shift+Ctrl+Z (Shift+Ô+Z on the Mac) to move forward in time (down the history list).

Looking at the History Options Dialog Box
The History palette has four options that change its behavior. To access these options, choose History Options from the History palette pop-up menu to open the History Options dialog box. The dialog box offers these options:

-->Automatically Create First Snapshot: This option, selected by default, tells Photoshop to create a snapshot of the image when you first open it, before you make any changes. You can return to this snapshot at any time by clicking its name in the History palette. Keep this option selected. That way, you can always return to your original image if necessary.

-->Automatically Create New Snapshot When Saving: This option tells Photoshop to create a new snapshot each time you save the image. If you’re like me and save every couple of minutes, you probably won’t want to select this option; otherwise, you end up with a palette full of unwanted snapshots.

-->Allow Non-Linear History: This option makes editing or deleting a state without removing all the states that follow it possible. When the Non-Linear History capability is active, you can make an editing change to an intermediate state in the history list, perhaps save the edited state as a snapshot, or even delete the state, leaving the other steps below it unchanged. (When you delete a state you’ve edited, the edit you made is added to the end of the history list.)

Use this option with caution because steps are interdependent. A change you’ve removed may form the basis for another edit later on, so deleting it can cause weird results.

-->Show New Snapshot Dialog by Default: This option ensures that Photoshop asks you for a name for any new snapshot you create. Applying names to snapshots makes reminding yourself of the state of the image when you saved the snapshot easy.


Keeping the New Snapshot dialog box close at hand
If you want the New Snapshot dialog box to open when you create a new snapshot by clicking the camera icon, select the Show New Snapshot Dialog by Default option described in the preceding section.
Hold down the Alt key (Option key on the Mac) when you click the camera icon to access the dialog box even when the Show New Snapshot Dialog by Default option is deselected. If you remember this technique, you can alternate between creating generic snapshots and using the dialog box.

Removing a State and Clearing All States in Photoshop

To remove a state and all the steps that follow it, select the state and then do one of the following:
-->Press the Delete key.
-->Click the trash can icon.
-->Drag the state’s icon to the trash can icon.
-->Right-click the state (or Control+click on the Mac) and choose Delete from the contextsensitive menu that pops up.
-->Choose Delete from the History palette pop-up menu.

Clearing all states
You can clear all the states from the palette by choosing Clear History from the palette pop-up menu. To delete all the states except the last one in the history list, as well as keep the snapshots you’ve saved, choose Edit➪Purge➪Histories. You can clear or purge your history list when you don’t need the states that are included anymore, to save memory or to return to the original state of your document. Just be sure you’re really, seriously, not interested in going back again later to make changes because this command cannot be undone, with one exception. You can only undo your clearing or purging if you choose Edit➪Undo immediately after you execute the command.

Viewing an Image’s Various States in Photoshop

You can move back to any state listed in the History palette, remove a state to cancel a step, or perform other time-travel stunts with the History palette. The following sections outline some basic time-shifting techniques you should know.

Going back to a particular state
To go back in time and resume editing at a particular point, just click the state you want to return to. All subsequent states appear grayed out, or what Adobe calls undone. Then begin editing your image as usual. As soon as you perform a new step, all the states that follow your re-entry point vanish. It’s like applying the Undo command to a group of steps with one click.

If you intentionally (or accidentally) begin editing while a previous state is highlighted, and you change your mind, immediately undo your first action — press Ctrl+Z (Ô+Z on the Mac). The subsequent steps that were removed reappear.

Reviewing your image at different states
To review how your image looked at various previous states, just click the state you want to take a look at. (You can also drag the active state marker up and down the list.) The document image immediately changes to reflect that earlier state. You can move back and forth between any points in the history list if you like. As long as you don’t make any editing changes during your time-traveling jaunt, your current history list is preserved.

Introducing History palette options and tools in Photoshop

-->Snapshot thumbnail: This is a miniature image of the most recently saved snapshot image, which is a copy of your document with all the current states included.

-->Source state column: Click in this column next to a particular snapshot or state, and when you begin painting with the History Brush tool or when erasing with the Erase to History option, Photoshop uses the snapshot or state you select as the source.

-->History state: This is a particular step or edit in your document’s list of steps. An icon appears in this column showing what kind of action occurred in that state.

-->Active state marker: This slider points to the currently active state. You can drag it up or down to change the current state.

-->Create new document from current state: Click this icon to create a duplicate copy of your image at the currently selected state. Your new document starts out with a clean slate and an empty history list.

-->Create new snapshot: Click this icon to store an image of your document, preserving all the states listed.

-->Delete current state: Click this icon to remove a selected state.

-->Undone states: These are the grayed-out states that are undone when you select an earlier state in the list.

-->Open state: This is the original document when first opened.

-->Current history state: This is the active state you’ve selected in the history list.

Changing the default number of steps that the History palette displays in Photoshop

The History palette displays a list of each change you make to your image — every brush stroke you dab, every deletion you make, every layer you create — up to a default limit of 20 steps, or states. The list begins at the top of the History palette, and Photoshop tacks each new step on at the bottom. When you reach the limit of 20 steps, the oldest step (at the top of the list) drops off to make room for the latest one at the bottom.

If you move something repeatedly and don’t choose another tool, all the moves are considered a single step, until you do select another tool.

If your computer has lots of memory and you want to be able to move back and forth more than 20 steps, you can increase the number of steps to as many as 1,000 in the General Preferences dialog box. Choose Edit➪Preferences➪General (or Photoshop➪Preferences➪General in Mac OS X) and enter a new value in the History States box. Keep in mind that boosting this number can eat up your available memory quite quickly, because after you activate a higher number of states, Photoshop always stores up to that number every time you edit an image (even images with which you don’t contemplate needing access to more than 20 steps). A better choice may be to leave the states set to 20 and instead save snapshots of your image, as described in the following sections.

Understanding states and snapshots in Photoshop

You can’t go too far in your use of the History palette without understanding two important concepts, as well as how the concepts are different:
-->States: States are just another way of saying steps. At any given point in your imageediting activities, Photoshop saves your individual edits into states. By default, Photoshop remembers 20 states for an image.

-->Snapshots: You can save temporary copies of an image, each containing all its various states. For example, say you make six edits to an image before you take a snapshot. The snapshot shows the image, but it also contains a complete history of the six states. Make a few more changes, and take another snapshot: The new snapshot contains the six states you made previously, as well as any new ones.

When you have these concepts down, you can get to the business of understanding how the individual tools in the History palette use states and snapshots to help you go back in time (and back to the future again) to undo, redo, and modify each miniscule edit you make to your images.

Working with the Almighty History Palette in Photoshop

Undoing and redoing commands are kid’s stuff next to the power of the almighty History palette. Think of this tool as a recipe listing all the steps you took to cook up your image in its present state. Using the History palette, you can browse through the recipe and return to any step in the list to begin work anew from that point. In this mode, the History palette operates like a multistep undo process.

Reverting to What’s Saved in Photoshop

Revert replaces your current file with the last saved file, effectively wiping out everything you’ve done since the file was last saved. You can revert to the last version of the file by choosing File➪Revert (or by pressing F12). You lose all the changes in your current file when the last saved version replaces it on-screen.

On the surface, Revert seems like an all-or-nothing proposition to be resorted to only when you’ve given up all hope of salvaging the current file. However, that’s not necessarily the case. For example, you may find using Revert to produce two versions of an image beneficial.

Perhaps you’ve done some work on an image and now want to compare this version of the image with a version of the image that you apply an entirely different set of commands to. Just duplicate the current version (choose Image➪Duplicate) and revert back to its pristine state to apply the other effects. Then you can compare versions to see which you like best. (This tactic works only if you haven’t saved the file along the way, of course.) You can use Revert in this manner as many times as you like to create two, three, or more versions all based on one original image.

The Revert command is stored on the History palette, so in many cases, you can remove the Revert command to restore the file to its manipulated state once again. You find out how to remove a command from the History palette in the next section.

Revert restores only the last saved version of your image. If you open an image, make some changes, and then save it, Revert backtracks to that saved version, not to the original. That’s why working with a copy of an image is a good idea, in case at some point you really do want to go back to the original version.

Using the Undo Command in Photoshop

Your first stop in your journey through time is the Undo/Redo command. This command simply reverses the last action you took or reapplies it if you just undid something. For example, if you apply a brush stroke you don’t like, use Undo to remove that stroke. Then if you immediately change your mind, you can redo it.

To undo your last action, choose Edit➪Undo or simply press Ctrl+Z (Ô+Z on the Mac). Use Undo/Redo to toggle an effect on and off to compare the before and after effects quickly. For example, you can apply a filter, examine the results, and then flip back and forth between the filtered and unfiltered version by pressing the Undo/Redo shortcut keys rapidly. When you decide which way to go, stop. This procedure works best if you’ve chosen to press Ctrl+Z (Ô+Z on the Mac) to apply both Undo and Redo.

Remember that Undo/Redo works only for a single command. If you do anything else after applying a command and then change your mind, you have to resort to one of the other timetravel techniques described later.

If an action can’t be undone or redone, Undo/Redo is grayed out and unavailable. For example, if you apply a brush stroke and then save the file to your hard drive, you can no longer undo the brush stroke. (However, you can use the History palette to remove the brush stroke.

If you want to free the memory used by the Undo command, choose Edit➪Purge➪Undo. If the item is grayed out, the buffer is already empty. Note that this action cannot be undone, so only do it if you notice Photoshop acting sluggish.

Time Travel —Undoing in Photoshop

When Tom Wolfe said, “You can’t go home again,” he wasn’t talking about Photoshop. If you change your mind about something you’ve done and want to return to your starting place (or any point in between), Photoshop is very forgiving. My favorite image editor offers many different ways to reverse actions, undo what you did, reapply effects you’ve cancelled, and generally change your mind as often as a new apartment owner deciding where to put the couch.

Photoshop is the ultimate time machine. Not only can you reverse actions, but you can also go back to the future to restore them. This flexibility enables you to work on your image as you please, without worrying that a particular action will be locked in stone. Confident in your ability to retrace or repeat your steps as necessary, you can experiment, try different effects, and be much more creative.

Undoing What’s Done
Photoshop gives you two simple ways to undo your efforts: the Undo/Redo command and the Revert command. Both are easy to master, as described in the next few sections.