Sharpen Channels Separately
Certain images don't look all that good after being sharpened. For instance, when you sharpen a face, it sometimes seems to just fall apart, making the person look years older. Another example would be scanned images where color noise is exaggerated. In those cases, you should consider clicking through the channels that appear in the Channels palette and sharpening only the channels that would help the image. When it comes to skin, that would be the channel that is the lightest (red in RGB mode or cyan in CMYK mode) (Figure 12.64). For noisy images, you should avoid sharpening the channel that contains the most noise (usually blue in RGB mode or yellow in CMYK mode) (Figure 12.65). I don't use this technique every time I'm sharpening, but I'll think about it when sharpening the full color image makes it look worse than the original.
Figure 12.64. From left to right: red channel, green channel, blue channel. (©Stockbyte, www.stockbyte.com)
