Photoshop® CS5 Bible

Chapter 11. Channels

IN THIS CHAPTER

• Using the Channel Mixer to enhance grayscale

• Understanding the Channels panel

• Creating, duplicating, splitting, and merging channels

• Creating and using alpha channels

• Adding spot color channels to images

Color channels are a core component of both color and grayscale images. Color images are composed of separate color channels that, when combined, make up the colors in the image. Understanding the color channels and the tools that Photoshop provides will help you make better use of the color data in your images.

Photoshop provides two main tools to help you manipulate and manage the color channels in images: the Channel Mixer and the Channels panel. Using these tools, you can see, manipulate, and even create channels in your image to increase your options when making selections and adjustments.

This chapter discusses using the Channel Mixer to mix, swap, and combine the color data in your images and using the Channels panel to manage channels, create and use alpha channels, and create spot color channels.

Understanding Color Channels

In Chapter 4, we discussed how the images that we see are just light emitted from a computer screen or reflecting off a photo. We also discussed that the colors we see can be divided into the levels of three frequency ranges of light-stimulating receptors in the eye. Photoshop uses this same concept to represent digital images. Each pixel in a color digital image contains a series of values that define the actual color of ...