Chapter 14. The Wonders of Blend Modes
Blend modes permit you to mix the color of a 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 14.1. Here you see several clones of our bony old pal. Each one has been 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.
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