Denoise, DT versus RT

The photo was shot under poor conditions resulting in a lot of noise.

First of all I adjusted the exposure. Now there is a need to denoise the photo.

An easy,one minute adjustment in the RT 5.5 denoise module results in a much improved image. See the close up of the face of the boy.
I’m sure it can be done even better using wavelets or other advanced tools and I welcome suggestions.

But Darktable is another story all together. How can I get a similar (or better) result using DT?

I have uploaded the original RAW-file, PP3- and XMP-files.

Original photo

After having adjusted exposure

After denoise

DSC_0629.NEF (25.7 MB)
DSC_0629.NEF.pp3 (11.6 KB)
DSC_0629.NEF.xmp (6.8 KB)

1 Like

You might just want to continue here:

With Nik Dfine and RT I get this:

image

Hermann-Josef

Darktable 2.5

DSC_0629_01
DSC_0629.NEF.xmp (5,2 KB)

you can’t get the (almost) same result. dt has no “recover details” slider. RT is siginificantly superior to dt in terms of noise reduction. you can only get a very similar (or better) result with Ps-like image editing and sophisticated masks.

Regardless of what you can achieve with DT (I will have a go later with your photo and report back), to me the “good” result you obtained with RT is not good at all.

Denoise pumped to the max causes this over-plasticky result which does not look good. I mean, objectively not good. I understand that people have different taste and perhaps we’re getting used to the strong denoising that jpeg engines in all the phones (and also higher-end cameras, check my Fuji if I choose high denoise the mess it does), but I would remove color noise as much as possible and then leave the digital grain as it is.

We still love those old photos from shot on Nikons and Tri-X don’t we? Lots of grain in those prints. Grain is good! Digital noise too, if treated with respect.

5 Likes

Pay attention to other parts of the photo that are similarly illuminated and compare them to the face; e.g., the parquet floor. If it doesn’t look natural after the denoising, I would say that you have gone too far.

PS @obe, if you would like this to be a play_raw, please add a CC license. :wink:

1 Like

hi,

I mostly agree with you, but I’d be careful also with too aggressive chroma noise reduction. imho it’s much better to have a bit of rainbow dust than extreme colour bleeding

@agriggio Imagining a unicorn in a bloody war. :rainbow::unicorn::see_no_evil:

1 Like

Hi,
Here is a trial with darktable master:

Only one instance of denoiseprofile, in non local means mode, with parameters:

  • patch size 6
  • search radius 7
  • scattering 0.3
  • central pixel weight 0.15
  • strength 1.1

darktable 2.6.1

DSC_0629_01.NEF.xmp (5,7 Ko)

Tried first with RT 5.5 - not so pleased.
Then with DxO PL

Though all have problems with this region, DxO hurts most here:

2 Likes

Hmm strange. I have never seen something like this in DxO before :thinking:

It is a part of the photo. The edge is weak from the noise. Some special treatment might be in order.

image

This is my preliminary denoising. I like the result but I suppose more could be done.

1. PhotoFlow → basic raw processing → filmic (OCIO; very low contrast)
2. gmic → peak removal → remove hot pixels → guided filter

Here’s my take. As you see, still lots of “grain” visible but overall I prefer it to the fake ultrasmooth look you get when using overly aggressive denoising.

100% zoom:

the processing history (Darktable 2.6.1):
DSC_0629.NEF.xmp (5.5 KB)

3 Likes

One might try the equalizer module to take some of the sharpness out of the noise.

I recommend the following video on noise reduction with Darktable 2.6

I’m still perplexed by the equalizer module since it can be used for so many different things, so I’m curious to know how would you use it to “take some sharpness out of the noise” as you said?