On Rawtherapee 5.9 windows 64bit: When enabling the “wavelet levels” plug-in and underneath that enabling the “noise suppression” section I can adjust the sliders of just level 1, set the mode to aggressive, set the preview window to a 1:1 preview and then I can clearly see the effect of the slider on the preview image. It appears to be very effective in suppressing colour noise (specks of individual pixels with divergent colours). I have a camera without antialiasing filter and with fine details, it may typically show brightly coloured pixels of various divergent colours. The wavelet noise suppression plug-in appears to very affective at suppressing that judging by the 1:1 preview. But when I then export the image as a jpeg the noise suppression does not appear to have done anything. The coloured specks are clearly visible in the jpeg. Increasing the strength of the effect also does not seem to do anything with the jpeg.
Have other users noticed this as well and if so, could you fix or work around it?
Hi @Michael_Schagen, welcome to Pixls!
You give a not so detailed description of what you did, which makes pinpointing a possible issue/mistake rather hard. You also do not mention if this is specific to one image or something that you notice in general. Using the Wavelet Levels module can be tricky and has a lot of knobs and sliders to play with.
That being said: I never noticed the behaviour you are describing.
Here’s a rather simplified Wavelets Denoise workflow to start with that should give you some decent results:
- Set Complexity to Standard,
- Turn on Denoise and Refine and none of the other wavelet tools,
- Leave Mode as is (Conservative),
- Set Process to: One level , Level 1 and All directions,
- Set zoom level to 300% or 400%,
- Go to the Level 1 slider and move the bottom (Refine) slider all the way to
the right, - Move the top slider (Denoise) slowly to the right until you see a change happening,
- Move the bottom slider back to 0.0 (or there about, do not set it to a negative value),
- Set Process to: One level, Level 2 and All directions,
- Go to the Level 2 slider and move the bottom (Refine) slider all the way to the right,
- Move the top slider (Denoise) slowly to the right until you see a change,
- Move the bottom slider back to 0.0 (or there about, do not set it to a negative value).
Repeat this for levels 3 and 4.
- Set Process to: All levels, in all directions
- Set zoom to 1:1 / 100%
If you now turn off/on the Denoise and Refine tool you should see an obvious difference. The hard part in the above steps is knowing where to stop with the Denoise sliders. You’ll get a feeling for that when you use it more often.
If I follow the above steps and dial in rather conservative denoising settings on a 12800 ISO RAW, then export the resized (from 8280 width to 2560) jpeg (98, best quality), they look like this (500x500 crop at 100%):
Without wavelets denoise:
With wavelets denoise:
I see an obvious difference in noise (even on my second, not-so-good monitor).
The above is rather simplified and you can get (much) better result if you dial in all the correct settings for your image (not limited to wavelets), but that is a bit out-of-scope here. If you want to know more I advise you to have a look at @Andy_Astbury1’s videos that cover this topic (his RawTherapee playlist, search for the wavelet keyword).
Hi @Michael_Schagen, and welcome!
https://rawpedia.rawtherapee.com/Wavelet_Levels
Also: download the image of the particularly noisy girl
and work through this wonderful tutorial:
https://rawpedia.rawtherapee.com/Local_Adjustments#Using_the_Denoise_module
Have fun!
Claes in Lund, Sweden