Tuesday, August 6, 2013
Blending Channels Part II
More on how and when to use this powerful Photoshop tool
If you think you're not used to blending channels, think again. Every time you turn a color image into a black-and-white image, you blend channels. In a grayscale conversion, three channels are blended to create a single channel, while when using either Hue/Saturation or Channel Mixer, three channels are blended to equal RGB values. But, when it comes to color adjustment, blending channels is used infrequently, perhaps because it's so little known. Blending channels is a sophisticated adjustment method. In a majority of cases, you don't need a method that's this complex. Blending channels is best used in exceptional situations for enhancing originals with substantial problems. If you find that you use this technique frequently, you're probably not addressing the real problem—the quality of your originals. Nevertheless, when you run into files with severe problems, blending channels will often save the day.
1. Start with four copies of one image.
2. Convert three copies of one image into three different color spaces—LAB, RGB and CMYK.
3. Split Channels command to preview all the channels simultaneously.
4. Identify the problem channel.
5. Identify the channel that contains the best replacement information.
6. Hold the Shift key and drag the background layer of that channel (now a separate grayscale document) into the window of the color original. A new pin-registered layer will appear in the Layers palette.
7. Double-click on the new layer's icon activating the Layer Style dialog box.
8. Under Advanced Blending, check the channel to be affected.
9. Under Blending Options, set Blend Mode and Opacity.
10. Under Blend If, use the sliders to drop out the effect in shadows or highlights, if necessary.
11. Mask, if necessary.
12. For added effect, correct the tone of the new layer by grouping a Curves adjustment layer to it.
13. Repeat with the other channels as necessary.
John Paul Caponigro, author of Adobe Photoshop Master Class and the DVD series R/Evolution, is an internationally renowned fine artist, an authority on digital printing, and a respected lecturer and workshop leader. Get access to a wealth of online resources with his free enews Insights at www.johnpaulcaponigro.com.
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