TECHNIQUE 90: CLEANING UP DIGITAL NOISE Repeat this process on the Blue channel and then click the RGB channel to view the full-color image. Figure 90-2 shows a detailed view of the example image before (left) and after (right) fixing the noise through the channels. HINT: Although this method can remove much of the graininess from your digital file, if the original image quality is poor to begin with, you may still see some noticeable grain after this process.
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Figure 90-2
STEP 4 If your image seems a little bit too light or too dark, you can adjust the luminosity without having to use a Curves or Levels Adjustment. With the RGB channel still selected in the Channels panel, Ctrl+click/Ô+click the RGB channel thumbnail to load the image’s luminosity onto the Clipboard, and then press Ctrl+J/ Ô+J to create a new layer filled with the luminosity selection. Switch over to the Layers panel and you will see this new layer, which you can label as luminosity. To lighten the image, change this layer’s blending mode to Screen, or to darken the image, change the blending mode to Multiply or Darken. Figure 90-3 shows a comparison of the original image (top), the corrected image (middle), and the image with the extra luminosity layer (bottom).
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