I tried your image with a whole bunch of software: Lightroom CC, DxO Optics Pro 11 (prime NR), ACDSee U10, On1 Photo Raw and Affinity Photo. The original is quite noisy and the tricky task is to find a balance between removed noise and retained detail. It takes a lot of practice.
That being said, I got the best result by far with Affinity Photo, that I just tried out for one hour, better than LR and RT that I have been using for years. Go figure.
I think this topic has lost its purpose. Submitting endless variations which @Jessie dismisses as too denoised, not denoised enough, things all subject to taste, that won’t help anyone. We’re not learning from this, we’re just trying to stumble upon a combination which will please you, not us, so it would make more sense for you to do this. You seem to like the LR version which has nuked all color detail, I don’t. It would be interesting to see what can be done using various denoising techniques (“Noise Reduction” vs “Wavelet > Denoise and Refine”), but that’s not what’s happening here. You have RawTherapee, there is a preview, there are sliders and knobs, use them to tweak the noise reduction to your liking. No point keeping this going until someone stumbles upon right two-slider combination which is to your taste because it won’t work for other photos under different light using different camera parameters. Besides, there are other differences between the LR version vs other versions, such as in the tones and colors, which have nothing to do with noise reduction and which make comparing noise reduction impossible. To really compare noise reduction you should open the raw in RT, apply neutral, tweak the tone curves to improve the lighting (but keep everything else off), save a 16-bit compressed TIFF, upload it here, and then open that TIFF (not the raw file) in LR and in RT, turn everything off, enable only noise reduction, tweak.
I do mean this in a very friendly way.
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I agree that we should close this thread.
If I manage to get a good enough shot (portrait + high iso) I will post it in another thread.
I wanted to know if I have forgot/miss something in the way I can easily do noise reduction with RT, but it seems not.
Perhaps it has something to do about how I particularly like the way LR handle color/noise (which may not be to the liking of others), I don’t know.
My camera (Samsung NX1) do produce a high level of ‘pattern’ noise at ISO > 2000, it may not be the case for every camera.
Thanks everyone to have participate in this investigation, and I’m sorry if I have been able to produce a good enough example to have a better scientific approach.
It is difficult to get someone to agree to have his face posted on the internet. 
I didn’t mean to close it (we don’t do that here), just to re-focus!
OK, so to refocus: one thing I learnt from this thread is that you can simplify the nr workflow quite a lot, by pushing the luminance to 100% and work only with the detail slider (for chroma, auto global works nicely for me most of the time). Until now, I was using the flow suggested by rawpedia, ie increase the luminance slightly and then tweak with the detail slider. This works of course, but I was surprised to read that only adjusting detail while leaving luminance to 100% is also good. Indeed, I tired on a bunch of high ISO pictures of mine, and it works very well! This is a very nice tip IMHO. I think from now on this is what I’ll do by default.
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I’ve generally been quite fond of RawTherapee’s noise reduction and sharpening features, but I must say: Jessie really managed to come up with a super tricky example. 
And btw.: The zooming can’t be the reason why R.T. is not winning over LightRoom here, because both have been zoomed equally, so it’s a fair competition.
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Yeah, it was kind of an accidental discovery that somehow works very well. You can also use it with very low ISO images: by setting the detail slider to around 90, it can fully eliminate the subtle luminance noise in the smooth parts while keeping nearly all the details intact. I find this works much better than setting luminance to something like 5~10 and keeping details to 0, which is not strong enough to remove noises in the background and is already starting to destroy details.
I agree with all you say. Also, I’d like to add that I much prefer the rgb method to the default lab one. Not only it does a much better job (IMHO) at preserving colours, but it also allows to be less aggressive with nr in general, as the grain pattern it produces is much more pleasing (or better, much less disturbing 
than what lab gives. Has anyone had similar experiences? Perhaps it depends on the camera as well?
I already noticed that !
Try on a noisy photo of Imaging Resource’s still life … RGB denoise (EDIT: should) destroys the red textile while lab keeps some detail …
EDIT … I had not tried with recent RT … just remembered from the old RT forum … the reason for addind the Lab mode was that RGB mode destroyed the color … then Jacques added Lab mode which was better with colors
But looks like it’s the inverse now !!!
@agriggio Interesting. I made a comparison with this snapshot of my doggo I took tonight. This was shot on the Sony A6000 at ISO 6400, demosaiced with AMaZE and 3 steps of false color suppression, impulse NR set to 65 and used high quality automatic global for chrominance denoise.
Lab*, 100/30
RGB, 100/15 (lowered the detail slider to match the overall noise level)
The Lab* one seems to produces an image of higher contrast and if you zoom into 100%, you should see that Lab method also produces much finer noise patterns. However, the noise from RGB actually doesn’t look that bad when zoomed out, thanks to less contrasty shadows that help to hide these noises. Lab’s higher contrast also makes the fur look sharper.
Now onto colors. The first thing I noticed is that Lab* method tones the darker areas with an unnatural red, which I find very distracting. The RGB method on the other hand makes highlights a bit more saturated, which I think works well for this image. The main issue with RGB here is that it produces messy color blobs around the color transitions in the background, which is only barely visible in Lab method. Perhaps increasing the chrominance NR slider could help migrating the problem.
Hi @PkmX, thanks for the analysis! One more thing I discovered is that I prefer the results I get when using the “Standard” quality of NR instead of “High”. Although the latter does certainly a better job at reducing color noise, the drawback IMHO is that it “dampens” the colors too much, resulting in a “dull” image. See the two examples below (I downscaled the pics because I’m on a slow connection, but the difference should still be visible).
standard quality
high quality
＠agriggio Yes, I’m aware of that difference. That’s why in my reply above I suggested lowering the chrominance curve by a lot, which can recovery some of that colors lost without reintroducing noise. This works very nicely for low ISO images.
I think I should also take the opportunity to showcase how well RawTherapee can deal with extreme noise. Here is another image of the black dog that was shared in my PlayRAW thread, and this time it is shot at ISO 25600 on the Sony A6000 (APS-C), the maximum ISO allowed on the camera. The only light source was a street lamp about 7 or 8 meters away, and the subject being a black dog means that I had to crank the ISO all the way up to the maximum.
RAW Image
Eww, awful noises everywhere.
SOOC JPEG
Lots of details are smeared on the fur and there are still loads of noises visible in the background.
RawTherapee
All colorful noise are simply gone. The noise pattern in the background is fine-grained and unobtrusive, and nearly all details in the fur are still intact. This is seriously impressive in my opinion.
OK guys, how well could you process this image:
_IMG5577.DNG (12.8 MB)
I couldn’t do better than this:
@Trickortreat I think the main issue is that there is either motion blur or the town is slightly out of focus. There actually isn’t much noise in the image.
Here is my quick attempt:
By the way, the auto levels function in RawTherapee is totally messed up with this image, it sets lightness to some value >90. I guess this is due to the excessive amount of black in the image?
But your dog is the wrong colour and the grass has gone from green to orange-ish! I think the jpeg is a better record of the dog.
The color difference is caused by me using a different color profile, as well as changing the white balance plus some H-H adjustment in Lab* tool and finally applying a film emulation CLUT. With all these adjustments turned off, it looks fairly close to the RAW image:
Could you post your pp3, i like how you extracted more detail than me.
Center point is in focus, other is some lens issue because at f2.8 corners are somewhat soft and darker + there is noticeable field curvature
Yep - i got that lightness issue too, just dialed it down manually to 9
