As seen in digital photographs, noise manifests itself in two different forms, chroma noise and luma noise. While having no noise at all would be ideal, that is simply not possible at high ISO values. Luma noise tends to resemble the type of grain that would be seen in high speed film stock, while chroma noise characterizes itself as random color splotching across the image; especially in shadow areas. In general, people are not overly bothered by luma noise; however chroma noise has an unappealing effect on an image. Therefore while we can’t get rid of all noise from an image, removing the chroma noise improves things a great deal. The goal of this article is to present a quick and easy way to greatly reduce or eliminate chroma noise from an image using some simple layer techniques in Photoshop.
Check it out here.