Chapter 6: Blend Modes and Knockouts

Overview

Blend modes enable you to mix the color of one pixel with that of every pixel in a straight line beneath it. A single blend mode can pack as much power as a mask, a filter, and a retouching tool combined. And, unlike some of those combined options, blend modes don't physically alter an image's pixels ” they're temporary. As long as one image remains layered in front of another, you can replace one calculation with another as easily as you change a letter of text in a word processor.

To appreciate the most rudimentary power of blend modes, consider Figure 6-1. Here you have several clones of our boney old pal from Chapter 4. Each one was mixed with the background using a random sampling of blend modes from Photoshop's Layers palette. The skeleton image itself never changes; each repeated layer contains the same collection of pixels. In all, there are six layers : five skeletons and the background, each skeleton layer subject to the blend mode labeled in the figure.

Figure 6-1: Six identical layers mixed in a variety of ways with the background image via a different blend mode option.