When you have noise in an image, there’s a lot you can do about it. There are many ways you can reduce noise during postprocessing; you could even say there’s an art to it. Learning these techniques can improve good exposures and save others.
First, take steps to reduce noise at the point of capture. Favor low ISOs and avoid very long exposures. Next, use RAW-conversion software to reduce moderate amounts of noise. Finally, use Photoshop and third-party noise-reduction software for aggressive amounts of noise. The KISS principle applies. Use simple methods if they provide good results. Use progressively more powerful and sophisticated tools only as challenges arise.
In the January/February issue of DPP, I showed you how to reduce noise with the Photoshop filters Despeckle, Dust & Scratches, Median and Reduce Noise, and in the March/April issue, I showed you how to reduce noise using Adobe Camera Raw and Lightroom (an updated version of the March/April Revolution column will be available at the DPP website when you read this). In this column, I’ll show you how to reduce noise in Photoshop using a simple technique to blur the color noise and therefore dramatically reduce its prominence in the image.
On the one hand, it’s difficult to reduce luminance (light and dark) noise without compromising image sharpness; often, it requires careful application of specialized software. On the other hand, color-noise reduction is comparatively easy and has less severe side effects—typically, slight reductions in saturation, particularly along contours. You easily can reduce most chrominance (hue and saturation) noise using Photoshop.