How to Undo and Revert in Photoshop CS6
Adobe Photoshop Creative Suite 6 is very forgiving. This image editor offers many different ways to reverse actions, undo what you did, reapply effects you’ve cancelled, and change your mind as often as a new apartment owner deciding where to put the couch.
How to use the Undo command
Your first stop in your journey through time in Adobe Photoshop Creative Suite 6 is the Undo/Redo command. This command simply reverses the last action you took or reapplies that action if you just undid it. For example, if you apply a brush stroke that you don’t like, use Undo to remove that stroke. Then, if you immediately change your mind, you can redo it by using the command again.
To undo your last action, choose Edit→Undo or simply press Ctrl+Z (Command+Z on the Mac).
Press the Undo/Redo shortcut keys rapidly to toggle an effect on and off if you want to compare the before and after effects quickly. When you decide which way to go, stop toggling. This procedure works best if you press Ctrl+Z (Command+Z on the Mac) to apply both Undo and Redo.
The Undo/Redo command works for only a single command. If you do anything else after you apply a command and then change your mind about that command, you’ll have to resort to another fix-it technique.
If you can’t undo or redo an action, Undo/Redo is gray in the menu, showing that it’s unavailable. However, you can often use the History panel to remove the action.
If you want to free the memory that the Undo command uses, choose Edit→Purge→Undo. If the item is gray, the buffer is already empty. You can’t undo this action, so do it only if Photoshop is acting sluggish.
How to revert to what’s saved
Revert replaces your current file with the last saved version of the file, effectively wiping out everything you’ve done since you last saved the file. You can revert to the last version of the file by choosing File→Revert. Although you lose all the changes in your current file when the last saved version replaces it onscreen, the Revert command is stored on the History panel.