Chroma NR very aggressive in RT and ART

Processing
1

Hello all,
just took some test images with my new Viltrox lens. In my (former) default profile Chroma NR was enabled using automatic global.
When loading some images with autumn foliage and lots of branches, the result looked really strange!

Chroma-global
Chroma-global1159×977 592 KB

After some pondering I started with neutral and added filters … Chroma NR turned twigs blue and foliage colour would wash out some estimated 10 pixels into the blue sky.
This one is with Chroma NR disabled:
Chroma-off
Chroma-off1158×976 635 KB

Luckily Chroma NR is unneeded in most cases, so adding it by default was stupid. But, is this behaviour intended?

2

It’s a bit difficult to say without having an example pp3 and the raw. You use sliders I do not…

1 Like
3

Sorry, forgot about this :innocent:
DSCF8936.RAF (32.2 MB)

no Chroma NR:
DSCF8936_RT.jpg.out.pp3 (14.4 KB)

with Chroma NR:
DSCF8936_RT-1.jpg.out.pp3 (14.5 KB)

This file is licensed Creative Commons, By-Attribution, Share-Alike

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4

@Sunhillow I have started to notice the quite severe default chrominance NR too lately. I don’t think there has been a change in the way the NR is handled for a long time, but it seems worth investigating whether RT’s defaults are a bit too strong.

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5

Thank you for looking at it @Thanatomanic !
In most cases I did not see such damage. Maybe because here we have almost complementary colours?

6

@Thanatomanic I think there is a bug in Chroma NR. Load the attached chrominance curve. In my opinion it should disable chroma noise reduction, but it does not.
denoise_chroma.rtc (47 Bytes)

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@heckflosse Whatever it is, it was already working like this in 5.6 (which is the last version that I can get to build on an updated MSYS environment atm.

8

Just checked 5.0 R1, there it looks similar. 4.2 crashes on loading the RAF