Raw Therapee Noise Reduction


(Stampede) #1

I have been trying to get a handle on noise reduction in RT. I have processed the following image as good as I can. I wonder if I can get the noise down any more.

I followed along in the Rawpedia (RT Documentation) in the section on noise reduction. I still do not know the difference between luminance and chrominance noise. I basically move sliders around (while reading the manual) until I like the result.

Could I have done better with this picture? How?
Camera: Canon G7X Mark 2.

Raw file and processing profile here: https://filebin.net/9e0o85ox1ecml0ot


(Alberto) #2

Hi @Stampede,

I’m not an expert, so forgive my sloppy terminology, but you can think of chrominance noise as the “coloured stains” that you see when opening an underexposed image without any noise reducion. Luminance noise is essentially the “grain” that you see also when looking at a black-and-white picture.

that’s perfectly fine, I think :slight_smile:

Better is subjective, but here are couple of things I would do with your picture, FWIW:

  • use a dual-illuminant dcp profile for your camera. I generated one from dpreview’s studio scene (see this thread)
  • turn off “auto CA correction” in the raw tab. Unfortunately in my experience this setting has a negative effect in colour, which is especially visible in underexposed/high iso shots
  • use “colour propagation” for highlight reconstruction instead of blend, as it seems to work better here.

I also made a couple more tweaks to the noise reduction settings, because I don’t mind a bit of grain, but I don’t think this is that important.

Here is my result, just in case.


(Peter Lavender) #3

Had a quick go at it.

Depending on what you want to achieve is what will measure the final processed version. Are you trying to go for as little noise as possible, or recovering of colour contrast definition?

IMG_0300.jpg.out.pp3 (10.8 KB)


(Shreedhar Inamdar) #4

There is a noise reduction module in Wavelet Tab too. I used that and also changed the tone curve and reduced the contrast. Used Color Propagation Highlight recovery to get this:

IMG_0300.jpg.out.pp3 (11.3 KB)


#5

I know that the heading says RawTherapee, but…

a) How would @Carmelo_DrRaw treat the noise?

b) How would a skilled darktabler handle it?
Denoise (profiled) I presume, but what else?

c) Anyone still having a working copy of Nik Software’s Nik Dfine 2.0 somewhere available for a test?

Have fun!
Claes in Lund, Sweden


(Morgan Hardwood) #6

@Stampede I updated the Noise Reduction article in order to answer your question:
http://rawpedia.rawtherapee.com/Noise_Reduction


(Roel) #7

This is how I learned to do it: Darktable Tricks
Usually works wonders, though it is rather heavy to process.


(Stampede) #8

the example photos you added are great. Thank you so much!

I’ll reply to others later on today once I play around with my image some more taking in their suggestions.


#9

super soft version:


IMG_0300.CR2.pp3 (12.2 KB)
with some details enhanced:

IMG_0300.CR2details.pp3 (12.2 KB)


(Carmelo Dr Raw) #10

To be honest, I have never tried to fight the noise too much… if I have a noisy image, I very often go for a B&W version and try to turn the noise into “grain-like texture”.


(Phil Howcroft) #11

Wavelet noise reduction is my preferred way of removing noise . I don’t really understand it but I move the sliders around ( viewing at 100 percent) until I get a nice result. I always tend to do another edit after rawtherapee in GIMP , usually a tad bit of sharpening and if i want a mono I tend to use GMIC black and white enabling pseudo greys too :grinning: