Working with the Noise Reduction Controls

You use the Noise Reduction adjustment controls when you need to reduce digital noise in an image. Digital noise is often caused by shooting at high ISO settings in low-light conditions. When you reduce noise in an image, you often have to sharpen the image to prevent blurry edges or loss of detail. For more information about sharpening an image, see Working with the Edge Sharpen Controls.

Figure. Image before and after a Noise Reduction adjustment.
To reduce digital noise in an image
  1. Select an image.

  2. If the Noise Reduction controls are not shown in the Adjustments inspector or the Adjustments pane of the Inspector HUD, choose Noise Reduction from the Adjustments pop-up menu (or press Control-N).

  3. Reduce digital noise in the image by doing one of the following:

    • By default, the Radius slider is set to the left side of the slider control. Drag the Radius slider to the right to decrease digital noise in the image, or drag the slider back to the left to reduce the effect of the noise reduction.

    • Click the left or right arrow in the Radius value slider to adjust noise in the image by 5 percent increments, or drag in the value field.

      The left arrow increases noise in the image, and the right arrow decreases it.

    • Double-click the number in the Radius value slider, then enter a value from 0.0 to 2.0 and press Return.

      Figure. Controls in the Noise Reduction area of the Adjustments inspector.

    A value of 0.0 applies no digital noise adjustment to the image. A value greater than 0.0 reduces digital noise in the image.

  4. Maintain edge detail in areas of high contrast in the image by doing one of the following:

    • Drag the Edge Detail slider to the right to increase sharpness in areas of the image with high contrast, or drag the slider back to the left to reduce the sharpening effect.

    • Click the left or right arrow in the Edge Detail value slider to adjust edge detail by 5 percent increments, or drag in the value field.

      The left arrow decreases edge detail sharpening in the image, and the right arrow increases it.

    • Double-click the number in the Edge Detail value slider, then enter a value from 0.0 to 3.0 and press Return.

As you change the parameter value, the image is updated to display the amount of edge detail sharpening applied to it.

You can also brush the Noise Reduction adjustment on selected parts of an image. For more information, see Making Brushed Adjustments.