Reducing Digital Noise

Images shot in low light

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lIn the Layers palette, duplicate the original image layer by dragging the background layer onto the "Create a new layer" icon, or use Ctrl/Cmd-J

2 Using either the pulldown blending mode menu in the Layers palette or the shortcut Alt/Opt-Shift-L, change the duplicate layer's blending mode to Color and rename it "Color."

3 Zoom in to ioo% using View > Actual Pixels or Ctrl/Cmd-Alt/ Option-Zero and move around the screen to an area where the digital noise is clearly visible

4 Apply some Gaussian Blur using Filter > Blur > Gaussian Blur Use a very small amount-just enough for the noise to disappear

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There are many ways to reduce digital noise or color aliasing—the red, green, and blue pixels that often show up in low-light photographs. If the digital picture is in a Raw file format, you can use Adobe Camera Raw or your Raw converter to minimize the noise. Alternatively, you can try one of the many Photoshop plug-ins or image-editing techniques, often involving use of the Lab image mode, to help. Here, however, is a quick method that utilizes blending modes.

The camera was hand-held in exceptionally low light to get this shot in a nineteenth-century fortress; I had to push the ISO sensitivity up to 6400 to avoid camera shake

Original image.

Noisy surface textures

The digital noise was most obvious in this man's coat, but was made much less obvious with a Color blend layer featuring a Gaussian Blur radius of 10

Original image.

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An alternate approach

Selective reduction with masks

Original image.

Opacity: 100 %

Here is an alternative approach Don't copy the layer Apply Gaussian Blur until the noise disappears, then immediately select Edit > Fade Gaussian Blur and select Color from the mode drop-down box The blur vanishes, but the noise reduction remains

The recipe helped to reduce the noise in the paved areas of this photo

When parts of the image don't contain significant noise, consider masking the Color layer and limiting its effect on the composite image

Original image.

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Darken Multiply Color Burn Linear Burn

Lighten Screen Color Dodge Linear Dodge

Overlay Soft Light Hard Light Vivid Light Linear Light Pin Light Hard Mix

Difference Exclusion

Darken Multiply Color Burn Linear Burn

Lighten Screen Color Dodge Linear Dodge

Overlay Soft Light Hard Light Vivid Light Linear Light Pin Light Hard Mix

Difference Exclusion

Original image.

Opacity: 100 %

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