How to use Photoshop Channels and masks

The Channels palette stones colour information about an image and can also be used to store selections on a permanent basis.

Masks are created and used in a variety of ways in photoshop. The basic principle of masks is that you use them to protect areas of an image from editing that you carry out on the unmasked areas of the image.

Use Quick Mask mode when you don’t want to save the mask for future use. Layer masks control how different areas of pixels on a layer are hidden or revealed.

Covers
Quick Mask Mode
The Channels Palette
Saving and Loading Selections
Editing Alpha Channel Masks
Layer Masks
Channel and Quick Mask Options