Certain features of Photoshop are designed to enable a non-destructive workflow. These features allow you the maximum flexibility in your design by enabling you to change a design that isn't working, or to satisfy the whims of even the most fickle clients. Yesterday they liked blue, but today they demand periwinkle? Not a problem.
Most dialog boxes for the tools in Photoshop allow you to undo at least the most recent action. For example, say you're using the Levels command, and you don't like the last tweak you made. You can press Ctrl+Z/.cmd;+Z and go back a step.
If you've made a good many tweaks within a dialog box and find that you just want to start over from scratch, holding down the Alt/Option key on your keyboard switches the Cancel button to Reset (see Figure 6.5), which restores the default settings of the dialog box.
Layer masks (see Figure 6.6) are incredibly useful and a central pillar in the concept of the non-destructive workflow. Rather than deleting pixels or parts of a layer to composite it with other ...