What’s your preferred mode in the Denoise module? Nowadays it defaults to wavelets (I think it used to be non-local in earlier DT versions).
I use (mostly) non-local, since it give smoother results, but since I often do hue-specific edits, I also add wavelets-chroma-only preset instance of Denoise, to help with artifacts on high-ISO photos.
Which method do you think looks the best? My favorite approach for this photo of a (what seems to be) a grasshopper sitting patiently on a leaf of lily of the valley, is the last one.
I tend to stick to a wavelets chroma-only (U0V0) preset and only do luma (Y0) denoising if it’s really bad. Most of the time noise is only really noticeable when you zoom in or use heavy sharpening.
Noise reduction is always a tradeoff between removing the noise and keeping details. Also, we perceive luminance detail more readily than chroma detail. Which is why it’s useful to use separate denoising for chroma and luminance.
In my experience, the non-local means is more “aggressive” than wavelets, for that reason I prefer wavelets. I find that the defaults work reasonably well, unless the image is under exposed. Then the default is too weak, especially in the darker parts. Which is to be expected: where noise is concerned, adding 1EV in the exposure module is more or less equivalent to using double the ISO in the camera (for a reasonably modern camera).
I tend to use the default denoise profile settings and sometimes reduce the preserve shadows slider. If I need more denoising I use other modules and apply a details threshold setting to preserve the sharpness while reducing noise. I don’t try and use just denoised profile on a noisy image.
If you use any kind of sharpening / detail enhancement, restrict it to edges (switch to drawn or parametric masking, you don’t need to define any mask, but use the detail level slider in the refinement options) to avoid increasing the noise further.
For that fine noise salt and pepper noise you have the astrodenoise module that can often work really nicely also the surface blur module which is the old bilateral denoise module with the right touch can make that type of noise disappear without sacrificing too much in the way of details…
If you want to really deep dive DT denoising consider watching the videos (including the one listed as being for version 2.6) from a youtuber called rawfiner. I think he has 2 or 3 denoising videos and one on chromatic abberations…He was one of the primary contributors for these modules… He explains them in great detail including a demonstration of what you might call basic noise analysis and removing it channel by channel…
I’m often dealing with pics that are only really noisy in the shadows.
Denoise over and above defaults:
I reduce that shadows slider
I increase the power to 1.3 or even more.
Sometimes I go for non-local means, but that doesn’t cope with the noisy background on a dark stage curtain well.
I do wonder, why is the preserve shadows even there? Why would I want to preserve noise in the areas that it is most likely to be in? I must be missing something! —?
You possibly already have but everyone who wants to understand the denoise (profiled) module should read the manual. I would say even revisiting the manual after using this module for a while is a worthwhile exercise.
Thank you for that. I guess I’m looking at a specific genre where I am wanting to avoid noise on in-shadow skin, and I’m not seeing any problem in the rest of the image when I turn that slider down. But I’ll look more carefully next time.
