Sometimes 1-Pixel-Artifacts from X-Trans Demosaicing

Hello Community,
due to home office there is too much time to play around with photos!

I’d like to report some artifacts that appear in some cases with X-Trans images. When viewing in normal scale, the dots don’t stand out. But to adjust sharpening, I always use 100% view.

Here are three screenshots to visualize the problem:

  1. 3-Pass-Markesteijn

  2. fast

  3. using Iridient X-Transformer for demosaicing:

1-pass Markesteijn produces even more dots.

If necessary, I will upload the RAF and the DNG

Yes, please upload the RAF and the .pp3 you used

Okay, here they are:
DSCF4615.RAF (32.1 MB)
DSCF4615_RT-2.jpg.out.pp3 (12.8 KB)

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

Thanks for looking @heckflosse!

1 Like

Thanks a lot for the files.
There is definitely a bug somwhere. Left shows the dots, right does not show the dots. The only difference between left and right is, that in right I switched to Mono and then back to 3-pass (which should give the same result as in left)

1 Like

Can you post the content of your AboutThisBuild.txt ?

AboutThisBuild.txt (838 Bytes)

I use the newlocallab builds

Thank you, did not try this before. It is a nice workaround :+1:

No, the output jpeg shows the dots again

As expected…

At least I know now what causes the bug. And there is possibly already a fix in this pr:

Will check that now

1 Like

Here’s a before/after from above mentioned pr
left is using current (dev) behaviour, right is using camera wb for raw preprocessing


Very big Thank You for merging the Raw preprocessing WB branch into dev! :pray:

I did not merge yet.

Edit: Is saw, rom9 merged \o/

Ah no, he merged dev into his branch. Anyway, tomorrow it will be merged into dev I guess. Then maybe another day to merge dev into the other branches (newlocallab for example)

1 Like

Doesn’t matter if it will take a few days to merge into all branches! Your reaction time here is ultra fast


Merged into dev \o/


@jdc Any objections to merge dev into newlocallab? If not, I will do that…



I just push a change before.
but after no problem you can merge.

Thank you


1 Like


1 Like

Thanks a lot to @heckflosse and @jdc!
Just downloaded RawTherapee_newlocallab_5.8-1964-g0436674b3_20200515. When using Preprocess White Balance mode = Camera the dots are much less prominent than before. Switching to Mono and back to 3-pass lets them disappear completely.

That’s a bug , though an interesting one :wink:

1 Like

A nice looking bug :beetle: :upside_down_face: