Darktables export looks different to what darktable shows

Software darktable
1

Hi all,

I used darktable to reduce noise of a high ISO image. When I export that image as JPG (Quality 100), view it at 100% and compare the result to the image shown in darktable at 100% I can see that the exported JPG is not as soft as shown in darktable, but noisier/grainier.

You can see it in the screenshot I made, for example the structure of the white lines (on the left side you can see darktable and on the right the exported JPG).

Darktable_Export_Difference
Darktable_Export_Difference2530×1143 1.13 MB

Unfortunately I cannot share the whole image or raw file :confused:

When loading the exported JPG back in darktable I can see those noise/grain in darktable, too. So it does not seem to be related to the image viewer.

What can be the issue here?

Some notes:

  • I export at the same size as the original RAW file.
  • I use AMaZE as demosaic.
  • I tried different export formats using different bit depth.
  • The gamut check mode does not show anything, at least not in the mentioned white lines (see screenshot).

Best regards,
da-mkay

2

what denoising are you using? with what settings?
can you try other demosaic algos? (for me AMaZE works weird with high-iso)

3

I also tried the other two demosaic algos (PPG, VNG). The results are similar.

I use two “denoise (profiled)” instances.
One using chroma preset (wavelets auto) and manually set profile to “DSC-RX100M5A iso 1600”.
The other one using defaults (e.g. non-local-means), but again, I set the profile as above and increased the patch size to 7.

4

Disable high-quality export.

5

You mean setting “high quality resampling” to “no” inside the export panel?
That does not make a difference. Both, “yes” and “no” produce the more noisier JPG.