Weirdly behaving green color tint when opening .cr2 files

[Jan Delember]

Hi everyone,

I've been using Affinity Photo on Windows for about a year now and if there has been any question, either the tutorials or the manual could help me out. Now I'm running out of ideas, that's why I'm reaching out to you.

Since a couple of days the RAW-files (.cr2) have a mild to extreme green tint right after I open them. Also, the midtones are blown out, as Affinity shows with these yellow spots in the image. The respective .jpegs, which my camera takes alongside them, look just fine. I've attatched two screenshots, one of which is the RAW-file without any modifications and the other is the normal .jpeg. The fact that the tint is visible in screenshots rules out the possibility of a wrongly calibrated display (it's in fact not calibrated but that's another story) - at least, I'm thinking it does.

When opening the RAW-file on Affinity for Mac, the story is the same. But when switching the RAW engine to Apple's builtin one, the image looks fine... Could that mean that it has to do with Affinity's RAW engine? I have tried opening the files with an older version of Affinity (1.8.x) which clearly didn't have the issue at the time (I'd definitely have noticed...) but that still gives me the same greenish result.

Another weird thing is that the builtin Windows image preview (which does support RAW) shows the same tint. For about a second or so, it shows the embedded jpeg (perfectly fine colors) and then switches to the raw data and the colors are off again. That leads me to believe that it has nothing to do with the RAW engine...

To add to the confusion, some RAW images seem to be just fine. I believe that it has to do with the variety of colors and/or the dynamic range. Some photos with less dynamic range (no complete white and complete black in one photo) look just fine when opening them. The photos that I have attached have some bright white (the blanket) and some very dark tones (the cat's fur). All other photos with a similar dynamic range tend to consistently have this tint issue.

Honestly, I'm quite confused at this point. Is there something obvious I'm missing? I'm sorry that there is no real question I can ask... If you need any extra information, I'm happy to provide you with it. Also, if this is the wrong forum, I apologize.

Thanks for reading through this confusing mess. I appreciate your help!

By the way: my machine is an HP Envy x360, Windows 10 Education, Version 20H2

[NotMyFault]

Hi Jan,

you may have accidently activated all clipping alarms. Click these 3 icons once (shown inside big red frame in picture below) to deactivate.

I hope this solves the issue.

 

Regards,

Timo

 

[Jan Delember]

Hi Timo,

thank you for your help. Unfortunately, this does not solve the issue. The yellow spots disappear, of course. But I left all clipping alarms on intentionally, because I think that the green tint and the blown-out midtones are related in some way...

Still, maybe you are right and it's some quick setting I have to make to solve the problem...

Thank you for your time! Regards,
Jan

[NotMyFault]

Hi Jan,

is it possible for you to provide:

1. The CR2 file
2. The out-of-camera jpeg file (if available). Please zip it before upload to avoid the forum sw from modifying
3. A screeshot of your develop persona assistant

There are principle differences in how Affinity develops CR2 files compared to Canon in-camera procesing and DPP, see below.

Affinity (using a modified GPL engine for raw development) never achivies similar results vs. Canon. The most obvious difference is that Affinity does not apply any sharpening by default, whereas all camera vendors apply a sometimes big ammount of sharpening to cover the unavoidable bluriness caused by CMOS sensor array (bayer or X-Trans).

Using your Cr2 file and Canon DPP, i might spot what settings (in camera, or in Affinity) cause differences. Unfortunately, I cannot check this only with the screenshots you provided.

 

 

[Jan Delember]

Hi Timo,

I've attached the .cr2 and the .jpeg as well as a screenshot of the assistant settings which appear to be the same compared to your screenshot. I hope that this helps.

Thank you!

Regards,
Jan

IMG_5166.zip

[NotMyFault]

Thank you, Jan.

Nice picture BTW

You are right, there is a strange green color cast when opening the CR2 in Affinity. I'm checking against how Canon DPP and try to find the cause.

Stay tuned.

 

[NotMyFault]

Hi Jan,

To compare both files, you can use these steps:

1. new stack from both files, with alignment (scale, rotate, transform)
   1. The stack is required to perfectly align the images. Cacnon exports 6000x4000 by cropping some edge pixels which are mostly garbage after lens adjustments, but Affinity insits to keep them. This only causes trouble, as now the apsect ratio does not fit 3:2.
2. Ungroup to get rid of stack.
3. Crop to get rid of edge clutter
4. move the JPG file to top position
5. Set blend mode to "difference"
6. add a levels adjustment to amplify difference (move "white level" to 10%)
7. select scope and RGB parade
8. Slect one of the 3 RGB channels
9. Bright pixel: big difference. Dark pixel: small / no difference.

My file was >200Mb and too large to upload, so a made a downsized version.

As you can see, you have lots of variations in all 3 color channels, not only green. So it is by chance that the green color cast was spotted, and the other color casts not.

Another strong difference is that the Affinity developed image lacks most of the detail in the lower right corner (where the green cast is visible).

I can only repeat my strong recommendation to not use the Serif RAW engine, as it delivers inferior quality in case of CR2 files, compared to

1. Out-of-camera JPG
2. RAW deleoped by canon DPP (it is free for Camera owners). Slow, but excellent quality.
3. JPG developed by Apple RAW engine

For images where quality of RAW conversions matters, i always start with DPP, export as TIFF, and the polish with Photo where required.

RAW_Affinity_vs_DPP.afphoto

[Jan Delember]

Hi Timo,

22 hours ago, NotMyFault said:

Nice picture BTW

Thanks!

I really appreciate your in-depth analysis of the problem, awesome work! I wasn't aware of the issues the Serif RAW engine has with .cr2 files. But if I'm understanding it correctly, this could be fixed by an update to Photo, right?

I wasn't really aware of an alternative RAW developing program other than Lightroom (which I don't want to use) either. Thanks for pointing me in the direction towards Canon DPP, I'll give it a shot this evening.

Also, your guide for comparing two images on a per-pixel basis will certainly come in handy in the future.

So, in summary: Thanks a lot!