Photoshop® CS3 Channels and Masks Bible

Chapter 16. Using Alpha Channels and Quick Masks

IN THIS CHAPTER

• Saving and loading selections

• Editing channels

• Working with alpha channels

• Entering Quick Mask mode

• Painting and editing Quick Masks

• Changing Quick Mask options

• Applying filters to Quick Masks

Selecting areas on a Photoshop image is by far the most labor-intensive aspect of image editing. Using alpha channels and Quick Masks can make the selection process more efficient. You create alpha channel so that you can alter a selection with the painting and editing tools or store a selection for later use. Alpha channels are graphic representations of selections. They are actually grayscale images that can support up to 256 shades of gray. Unlike color channels, alpha channels do not contain color informa-tion. Instead, they are composed of values of gray that represent areas of opacity or transparency of a mask.

Quick Masks are similar to alpha channels but unlike alpha channels they are temporary masks. They also enhance efficiency by enabling you to make temporary masks using the painting and editing features. Quick Masks can be converted into selection outlines or stored as alpha channels in the Channels palette for later use.

Employing both Quick Masks and alpha channels into your workflow enables you to extend the capabilities of selection making into the painting and editing tools. Rather than being limited to the cumbersome selection tools you can produce selections with more accuracy and with variable edge softness for better ...