Creating Channel Masks from Scratch

Channel masks are easy to create and once created, are just as easy to modify. All you need is an open document, and access to the Channels palette. By selecting a painting or drawing tool, you paint the mask to define the selection area. The problem is you can't see the image, you only see the mask. What you need is the ability to view the mask and the image, almost like a piece of tracing paper, and then use the drawing tools to paint (trace) the portions of the image you want to select. The secret to viewing the image as you create the mask is to temporarily enable or show, the composite channel. In fact, the composite channel acts like a toggle switch—when it's showing, you see the image and the mask like tracing paper, when it's hidden you only view the mask.