What kind of image noise is this?

The here presented photo is not of great interest, but what I would like to know is if the noise is visible to other users, certainly in the shadows?

When I edit this for practice colors and details are way off, certainly when I try the tone equalizer.

Could be that technical aspect of how the photo was taken be wrong, shutter speed, aperture etc.

IMG_4636.CR3 (32.7 MB)

I’m not sure I understand what you mean by this. It would help if you could share an example.

The noise example:

I don’t see anything strange here, just your typical run-of-the-mill shadow noise. All cameras have some amount of noise in dark areas. Denoise (profiled) deals nicely with the chroma noise, and contrast eq can be used for the luma noise.


I tried that on the same subject but photo that was better exposed (I think).

Added denoise profiled:

Added contrast equalizer:

One of the possibilities to heal that in a photo?

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Did you try adjusting the preserve shadows slider in denouse??

Heal what exactly? You need to explain what your problem is in much more detail. Right now we’re basically left to try to guess it.

Yes you are right.
It deviated somewhat.
I would like to know how to eliminate ash much possible that shadow noise in camera. Because I think I’m exposing wrongly.

From the example I am not sure but deduce the OP wants a perfectly smooth surface. From what he provided it seems over done ie I think he is using CEq to tackle noise but has lost detail in the process… I personally only just added about 3.5 ev… disabled exposure comp and put on lens corrections and tried denoise profiled and it was pretty good out of the gate… I just dialed back the preserve shadows slider but left in some shadow grain…to me that looks normal… it might be pixel peeping and over denoising …but again I am not certain…

This was just to check noise I didn’t try to sharpen tone map or otherwise modify the image…

Just use profiled denoise… in a few instances you can boost strength, but for shadows just adjust the preserve shadows…drop the slider slowly until you hit the desired point but remember that luma noise/grain gives you detail… if you hammer it then you will get a plastic looking image…

If you get real salt and pepper stuff you can also try astrodenoise as an extra instance… I set the patch to 4 and then drop the strength as low as I can to remove what I want but not kill the detail… you can also introduce masking to protect areas from being too harsh with denoise or directing it if you are going to be harsh and save parts of the image from that effects

You are. In particular, you are underexposing quite a bit while using a needlessly high ISO.

Here’s how much darktable wants to increase exposure:

There are two things that cause noise:

  1. Shadows. All digital cameras will have noise in deep shadows. Newer models will typically have less, but it’s always there.
  2. High ISO. The higher the ISO, the more noise. Again, newer cameras are better, but even the best eventually show ISO noise if you crank it high enough.

In this case, instead of [f/4, 1/640", 500 ISO] you could have have used [f/4, 1/125", 100 ISO] which would give the same overall exposure, but get rid of the ISO noise. You would still have shadow noise, though. To also get rid of that, you could use a slower shutter speed and/or wider aperture.

I recommend you watch this tutorial (you can skip part 1), it will teach you the essentials of exposure:


Given that it’s about 2,5 / 3,5 EV underexposed it’s quite normal to have some noise in the shadows.

IMG_4636.CR3.xmp (12.3 KB)

Not sure if i can post an edit due to the lack of some license for the file.


I’ll post as a screenshot but will delete if the OP wishes…

IMG_4636.CR3.xmp (13.3 KB)

Once you understand how to properly expose, I suggest learning about ETTR (exposing to the right). Here’s an article on that:


This is your image and histogram set to exposure and white balance as shot in camera. It is extremely underexposed and that adds a huge amount of noise. DT has a wonderful set of modules to fix this noise but it is best to get the exposure correct in the camera going forward.

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I just learnt something new today from @priort and that is to experiment with the preserves shadow slider in the denoise (profiled) module. Lowering this slider greatly helped with your image.


Also, take a look at this:

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