If the image you have opened has single pixel spots or noise you can use the Clean image tool to reduce or eliminate it. Examples of such images are those that include grain from photographic film or images from a digital camera with a “dead pixel”.
Eliminating spots and noise will not only improve the image but will also result in smaller JPEG and GIF images.
With the Noise Reduction tool turned on single pixel spots will be automatically removed.
Move the three sliders to achieve the noise reduction effect you require.
The example below shows the effect of the Noise Reduction tool:
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Note: The clean image tool can also be useful if you have amplified compression noise or the image grain using the enhance tools. Also note that JPEG compression (especially with MagiCompression) will reduce this image noise as well.
See also
Online Animated Tutorials