ptg Working with the History Panel Introduction Adobe introduced the History panel in Photoshop 5, and the graphic design world hasn't been the same since. On an ele- mentary level, the History panel gives you the ability to per- form multiple undos. Think of History as a magical mistake correction tool that never wears out. However, the History panel does much more than give you the ability to go back in time and correct your mistakes. The History panel is simply a tool, but when you combine the power of the History panel with the History brush and the Art History brush, you have a trio of tools that can take your creative designs to the next level and beyond. Adobe Photoshop gives you two ways to use the History panel—linear and non-linear. The linear mode helps you keep track of your recent steps, and erases any steps that interfere with a linear flow to the panel. The non-linear mode pre- serves all the steps (linear or non-linear), and is useful when you need to think outside the linear box. Photoshop raises the bar with the History panel by giving you the ability to record and save the commands performed to a document in a text file. Now, you can finally know exactly what you did to an image. And since the document can be printed, you can create History text documents of your favorite restoration and manipulation techniques, and save them. In addition, when you combine the History brush with the History panel, you have an awesome creative tool that can't be beat. In fact, it's even possible to convert the Eraser tool into a History brush. 6 6 What You’ll Do Set History Panel Options Work with Linear and Non-Linear History Control the Creative Process with Snapshots Duplicate a History State in Another Document Save the History State of a Document Review the History State Text File Combine the History Brush with a History State Use the Art History Brush Change the Eraser Tool into the History Brush Control History States 127 From the Library of Wow! eBook ptg 128 Chapter 6 Working with the History panel requires a firm understanding of how the panel functions, and what you can and cannot do with History. The History panel records your steps as you work through a document. A step is defined as a specific action, such as creating a layer or adding a brush stroke. Every time you perform an action, a step is recorded in the History panel. The History panel gives you the ability to go back to a previous history state, which is the same as performing an undo com- mand. You can perform multiple undo commands up to the number you set in Photoshop preferences for the History States. In addition, the History panel creates snapshots of the document. Snapshots are images of the current state of the document. Snapshots are used in conjunction with the History and Art History Brushes to create special effects. Setting History Panel Options Set Number of History States Click the Edit (Win), or Photoshop (Mac) menu, point to Preferences, and then click Performance. Enter a value from 0 to 1000 for the number of steps recorded in the History States box. Click OK. 3 2 1 2 3 Did You Know? You can duplicate a History State. Hold down the Alt (Win) or Option (Mac) key, and then click the History State you want to duplicate. You can use keyboard shortcuts to perform multiple undos. The History panel represents the ability to perform multiple undo commands. However, when you press Ctrl+Z (Win), or A+ Z (Mac) you only move back and forth between the last two commands, just like a normal undo. To perform multiple undo commands, press Ctrl+Shift+Z (Win) or A+Shift+Z (Mac) to move forward through all your History steps, or press Alt+Shift+Z (Win) or Option+Shift+Z (Mac) to move back- wards through the available History steps. From the Library of Wow! eBook ptg Chapter 6 Working with the History Panel 129 Set History Options Select the History panel. Click the History Options button, and then click History Options. Select the check boxes for the History Options you want to use: ◆ Automatically Create First Snapshot. Creates a snapshot (image) when the document first opens. ◆ Automatically Create New Snapshot When Saving. Creates a snapshot every time you save the document. This is useful for keeping track of the changes made to a document. ◆ Allow Non-Linear History. Allows you to operate History in a non-linear state. ◆ Show New Snapshot Dialog By Default. Opens a dialog box with options each time you create a new snapshot. ◆ Make Layer Visibility Changes Undoable. Instructs Photoshop to make any changes made to a layer's visibility undoable. Click OK. 4 3 2 1 3 4 2 1 From the Library of Wow! eBook ptg 130 Chapter 6 The History panel records each step performed on a Photoshop docu- ment in a linear fashion from top to bottom. However, the purpose of the History panel is not to simply record your progress through a docu- ment; it's there to help you make changes and go back in time to cor- rect mistakes. Photoshop gives you two History panel modes—linear and non-linear. When you work in a linear History panel, clicking on a previous step causes all steps underneath to become grayed out (unavailable). If you then add a step, the grayed-out steps are removed and the new step is added to the bottom of the list. A linear panel is organized and very RAM efficient; however, once a History Step is removed, it cannot be retrieved. When you work in a non-linear History panel, clicking on a previous step does not cause the steps underneath to become grayed out. If you then add a step, the new step is added to the bottom of the History panel. The new step represents the charac- teristics of the step you selected, plus any added actions. A non-linear panel is not organized and consumes more RAM. Its advantage lies in the fact that History steps are not deleted, they are simply reorganized. Working with Linear and Non-Linear History Work with Linear History Select the History panel. Click the History Options button, and then click History Options. Clear the Allow Non-Linear History check box, and then click OK. Work in the document until you have generated 10 or 15 steps in the History panel. Move halfway up the History panel, and then click on a step. The steps below the selected step turn gray. Perform another action to the image. The grayed steps are removed, replaced by the latest action applied to the image. 6 5 4 3 2 1 5 6 2 4 1 From the Library of Wow! eBook ptg Chapter 6 Working with the History Panel 131 Work with Non-Linear History Select the History panel. Click the History Options button, and then click History Options. Select the Allow Non-Linear History check box. Click OK. Work in the document until you have generated 10 or 15 steps in the History panel. Move halfway up the History panel, and then click on a step. The steps below the selected step do not change. Perform another action to the image. The new step is added to the bottom of the History steps. 7 6 5 4 3 2 1 6 7 2 5 1 Did You Know? You can quickly purge the History States, and therefore recoup addi- tional RAM. Hold down the Alt (Win) or Option (Mac) key, click the History Options button, and then click Clear History. But be warned; there is no undo available. You are stuck with your decision. You can reduce memory usage by using linear history. Non-linear History requires more RAM to maintain. If you don’t require a non-linear history and want to decrease RAM usage, then you can turn it off. In the History panel, click the History Options button, click History Options, clear the Allow Non- Linear History check box, and then click OK. 4 3 From the Library of Wow! eBook ptg 132 Chapter 6 The History panel contains more than just steps; it also holds Snapshots. A Snapshot is an image of the document as it exists at the time the snapshot was taken. The History panel can hold as many snapshots as needed, and they are not subject to the number of History States you chose in Preferences. That means they stay with the docu- ment throughout the creative process. By default, Photoshop takes a snapshot of the image when it first opens. This snapshot represents the original state of the image, before any adjustments or modifications are applied, and is identified with the file name of the image. It's a good idea to create a snapshot every time you make a major change to the image. That way, if you want to start all over, all you have to do is click on the snapshot, and Photoshop returns you to the moment in time in which the snapshot was created. It's like having your own personal time machine. Controlling the Creative Process with Snapshots Create Snapshots Select the History panel. Click the History Options button, and then click History Options. Select the Show New Snapshot Dialog by Default check box, and then click OK. Perform several actions to the image. Click the Create New Snapshot button. Type a name for the new snapshot. Click the From list arrow, and then click a save image information option: ◆ Full Document. Saves the entire visible image and all layers. ◆ Merged Layers. Saves only the merged layers. ◆ Current Layer. Saves only the active layer. Click OK. 8 7 6 5 4 3 2 1 2 6 7 5 8 1 From the Library of Wow! eBook ptg Chapter 6 Working with the History Panel 133 Here's a tool to help you gain control over the creative process, and save you a lot of time and effort as well. The History panel lets you create new documents based on a specific History step or snapshot. For example, you're working on a complicated image, and you want to isolate a portion of the image in another document. This will not only help you reduce the clutter, but working on a portion of the image in a separate document creates a document with a much smaller file size, and that will help Photoshop work faster. Duplicating a History State in Another Document Create Another Document Select the History panel. Click on the snapshot or History State you want to use for the new document. Click the Create New Document From Current State button. Photoshop creates a new document based on the selected snapshot or state. The new document's History panel contains one snapshot or one state. IMPORTANT Snapshots are not saved with the Photoshop document. When you reopen a document, the History panel will display one snapshot of the current state of the image or one History state. 3 2 1 2 3 1 New document based on the selected snapshot or state. Did You Know? You can save RAM by using the History panel. When you create a new document using the History panel, it’s very RAM efficient, as opposed to the traditional copy and paste method. From the Library of Wow! eBook . non-linear), and is useful when you need to think outside the linear box. Photoshop raises the bar with the History panel by giving you the ability to record and save the commands performed to. state. ◆ Show New Snapshot Dialog By Default. Opens a dialog box with options each time you create a new snapshot. ◆ Make Layer Visibility Changes Undoable. Instructs Photoshop to make any changes. in Preferences. That means they stay with the docu- ment throughout the creative process. By default, Photoshop takes a snapshot of the image when it first opens. This snapshot represents the