With varying degrees, all digital cameras produce electronic noise, extraneous pixels sprinkled throughout an image. Higher ISO, underexposure, long exposure, and oversharpening can increase this effect. Lightroom's Noise Reduction feature can easily reduce the effect of electronic noise, while maintaining image detail.

Lightroom's Noise Reduction controls are found under the Detail pane.

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Figure 4-48

Noise isn't necessarily bad. It can give an image dimension and authenticity.

Examine Image First

Noise isn't always apparent when you examine an image at low magnification. Use Lightroom's magnifying tools to enlarge your image after applying tone and color controls (but before applying additional sharpening), and the noise will become apparent.

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Figure 4-49

Pay particular attention to areas of continuous tone and shadow areas. Note the makeup of the noise. Does it look like a colored patchwork quilt? Or is the noise speckled and monochromatic?

Some images actually contain a combination of chromatic (color) and luminance (monochromatic) noise. Getting a handle on the type of noise will help determine which Lightroom control —Luminance or Color, or both—will be more effective.

Noise Reduction Procedure

To begin the process of noise reduction, follow these steps:

  1. Select the Detail pane. If you are working on a RAW file, you'll notice the default Color setting is 25, while Luminance is set to 0. Unlike the Sharpness Amount setting number, 25, which is a relative value based on the type of camera you used, the Color setting is an absolute value. This value is applied generically, which may or may not be right for your camera or image, but it's almost always a good starting point.
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    Figure 4-50
  3. Enlarge your image preview to at least 1:1 (100%), preferably higher. (Clicking on the [ ! ] icon, if present, will automatically enlarge your image.
  4. Start by sliding the Color slider to the left, down to 0. Next, move the slider incrementally to the right, increasing the value. This affects the chromatic (color) noise and leaves details found in the Luminance (brightness) channel alone for the most part. If you go too far with the Color setting, you won't lose detail per se, but you'll compromise color accuracy.
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    Figure 4-51
  6. If increasing the Color value doesn't do the trick, set it to zero and use Luminance. Go easy and increase the value incrementally. When working on the Luminance channel, you can quickly compromise image detail.
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    Figure 4-52
  8. Sometimes, a combination of Luminance and Color settings produces the best result. You'll have to experiment to get the correct combination, as the correct values vary from image to image. Remember the trick is to reduce noise without losing too much image detail.
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    Figure 4-53
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Figure 4-54
Figure 4-55

Making a Noise Reduction preset

Once you find an optimal setting for your camera, at a frequently used ISO, you can save specifically those settings and apply them to other similar images. To do this:

  1. Select the [+] sign in the Presets tab.
  2. In the New Develop Preset dialog window, select Check None (this unchecks all). Then check Noise Reduction.
  3. Name your setting and click Create.

The preset will now show up in the Presets pane in one of your Users folders as well as in the Import dialog box, many contextual menus, and in the Library module's Quick Develop pane preset pop-up menu. If you are applying a preset from the filmstrip hold the Ctrl key (or right-click) and click on one of the selected thumbs. Be sure to click on the image area of the thumb, not the edges.

If you find Lightroom's Noise Reduction controls don't take you far enough, open Photoshop and use its more powerful, and feature-laden, Reduce Noise filter instead.



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