Photoshop CC: The Missing Manual

Chapter 6. Understanding Channels

At the heart of any Photoshop file lie channels—storage containers for all the color information in your image, selections you’ve saved, masks you’ve created, and instructions for printing with special inks. Channels sound intimidating at first, and folks have been known to shudder at their mention and avoid them completely. But to really understand Photoshop, it’s good to get a grip on channels. Luckily, you don’t need a PhD to do that—just a little patience.

This chapter gets a little technical at times, but if you soldier through, you’ll be rewarded with wisdom that’ll help you perform some amazing pixel wizardry. You’ll get a warm, fuzzy, enlightened feeling as you learn to:

• Use channels to make complex selections and masks (Loading an Alpha Channel as a Selection).

• Map one image to the contours of another (Mapping One Image onto Another).

• Create a beautiful black-and-white image from a color version (pages Multichannel Mode and The Lightness Channel).

• Perform highly targeted color adjustments (see Figure 10-23 on page 394).

• Sharpen your images without introducing noise (Sharpening Individual Channels).

And that’s just the tip of the iceberg. Everything you do in Photoshop involves channels (well, save for working with paths and text, which you’ll learn about in Chapters Chapter 14 and Chapter 15), so it’s important to get familiar with them. If you understand how Photoshop does what it does, you can make it do even more in less time and with less ...