Today’s Question: Should you do noise reduction before you start editing an image or after?
Tim’s Quick Answer: I recommend applying noise reduction early in your workflow for optimizing a photo, though depending on which software you’re using that timing may not be as important.
More Detail: Various adjustments can amplify the appearance of noise in an image or make the noise more problematic. For example, sharpening involves an enhancement of edge contrast, and this can cause the noise to be exaggerated to some extent. Because of these issues I recommend applying noise reduction as early in your workflow as possible.
However, the software you’re using may make this timing less critical. For example, if you’re using Lightroom Classic to optimize your photos, the normal noise reduction that can be applied manually can be used in any order. It doesn’t matter whether you apply this noise reduction before sharpening or after, for example, because the adjustments aren’t applied directly to the image. Rather, the adjustments effective represent metadata values, and they aren’t applied until you create output from the source image, such as when exporting a derivative copy.
In situations where the noise reduction is being applied to the image before other adjustments, I do recommend applying noise reduction as one of the first adjustments to an image.
For example, if you’re going to use the AI Denoise feature in Lightroom Classic (or Camera Raw) that should be the first step you apply. After that noise reduction is applied to the image you can continue with any other adjustments in any order you prefer.
Whenever noise reduction is actually altering pixel values in an image, I recommend applying that noise reduction first (or as early as possible). In situations where the adjustments aren’t altering the pixels directly, such as with most adjustments in the Develop module in Lightroom Classic, the various adjustments can be applied in any order you’d like.