Setup darktable for Sony a7c ii to fix color shift/tint

Software darktable
1

Hello,

First of all, I understand that darktable does not aim to match the camera’s JPEG. I’m using the JPEG only as a reference because its colors are quite close to those I originally perceived in daylight. I’m not looking for an exact JPEG match; however, the initial result is very far from neutral.

I have been using darktable for about five years, so I’m familiar with scene-referred workflows and can usually work out how to achieve a particular result. However, I’m currently at a loss.

I recently bought a Sony A7C II, and I don’t have any presets for this camera yet. I loaded several test shots into darktable and was disappointed to find that every image had a strong greenish tint. This does not seem to depend on the lighting conditions—I tested both artificial light and daylight.

I also tried correcting the white-balance coefficients using the D65 procedure with an LED that should be approximately D65. However, the results were almost identical to those from the original setup.

What I’m trying to understand is why the colors differ so much from the “true” colors. This is not primarily a question of saturation or contrast; the green tint seems quite obvious to me.

I would like to create a preset for this camera that produces approximately correct colors as a starting point.

Based on other discussions, I could use an ICC input profile, such as one created with Capture One, or use the color calibration module. However, I suspect that color calibration may not be the right approach, since the result would not be generic—is that correct?

I have uploaded the ARW file, the XMP sidecar file, the camera JPEG, and the JPEG exported from darktable.

The images are licensed under CC0. I’m using darktable version 5.6.1.

Any help would be greatly appreciated.

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20260920_181604_exported
20260920_181604_exported7032×4688 11.4 MB

20260920_181604_from_camera
20260920_181604_from_camera7008×4672 18 MB

20260920_181604.ARW (37.8 MB)
20260920_181604.ARW.xmp (1.4 KB)

3

I had a similar problem with my EOS M6 camera, ba at that point I thought it might be camera specific and tried to do my best with color primaries to get the colors right. But now I feel that I am missing something fundamental here.

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That is my experience with my Sony A7iii as well. I would not call it a strong tint but even in my light room days I remember constantly correcting for a green tint.

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darktable 5.6.1 under linux. Just AgX, no color grading. Does not look greenish to me.

screenshot
screenshot1920×1160 559 KB

20260920_181604.ARW.xmp (6.9 KB)

1 Like
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@stakaz welcome! Please down size and compress the jpegs that you post! 12 &18MB is way too large

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Thank you both for the quick answer. The AgX is new to me, but as I can see you do not use dhe color calibration at all? When I use AgX and no color calbration the image looks not green at all, but with color calibraion reset to “default” which means the white balance coming from camera, I think, the gree ncolor persists.

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Hello, sorry. I will do this next time. Sorry for this.

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Was the shift constant as well? My feeling is that it is present in the same way in each image.

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Possible. The docs also hint at a systemic problem: darktable user manual - color calibration

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Yes, I tried this:

Some cameras, most notably those from Olympus and Sony, have unexpected white balance coefficients that will always make the detected CCT invalid even for legitimate daylight scene illuminants. This error most likely comes from issues with the standard input matrix, which is taken from the Adobe DNG Converter.

It is possible to alleviate this issue, if you have a computer screen calibrated for a D65 illuminant, using the following process:

Display a white surface on your screen, for example by opening a blank canvas in any photo editing software you like
Take a blurry (out of focus) image of that surface with your camera, ensuring that you don’t have any “parasite” light in the frame, you have no clipping, and are using an aperture between f/5.6 and f/8,
Open the image in darktable and extract the white balance by using the picker tool in the white balance module on the center area of the image (non-central regions might be subject to chromatic aberrations). This will generate a set of 3 RGB coefficients.
Save a preset for the white balance module with these coefficients and auto-apply it to any color RAW image created by the same camera.

but it did not improved anything, unfortunately.

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I sometimes get an odd behavior in darktable. When using color calibration CAT pipette default on (nearly) the whole image, the white balance reports an error. Setting white balance from “user defined” to “as shot to reference” gives a slight tint. Going back to color calibration and setting white balance with CAT and pipette again, give “realistic” colors again.

In summary, set white balance to “as shot to reference” or “camera reference” and using CAT afterward results in “good” colors.

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I could not reproduce this.

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What happens, when you apply my sidecar file?

20260920_181604.ARW.xmp (6.0 KB)

1 Like
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Can you do a screenshot for your color calibration module with the color area mapping expanded?

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This looks way better. However, if I interpret it correctly, you set the white balance in the color calibration module manually. This would be needed for each image, so not a good way to have a preset. I also have found that there is an option as shot in camera in color calibration well. This looks better, also.

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This are the settings as applied in the provided sidecar:

image
image678×766 50.3 KB

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Screenshot
Screenshot1920×1160 596 KB

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I figured something out with Colour Calibration recently. Its default is ‘as shot in camera’ but if it thinks the CCT is close enough to daylight, it picks the ‘daylight’ option and uses different correction numbers. You can switch to ‘custom’ or ‘as shot in camera’ in the dropdown and it will go back to the ‘more accurate’ default. I’ve done this, and no other corrections except a little exposure, with your raw (and white balance module set to ‘camera reference!’). Does it look better? I might have some more things to try.
You can set the ‘as shot in camera’ dropdown in CC as a preset, which might be what you’re looking for. xmp attached below.

20260920_181604
20260920_1816042109×1406 301 KB

20260920_181604_01
20260920_181604_012109×1406 302 KB

20260920_181604.ARW.xmp (8.4 KB)

Someone posted about trying to fix the Sony WB discrepancy recently, but there hasn’t been a follow up :confused:

Second thing: It’s funny you mention you used to have an M6. I’ve only ever used an M6, and I’m very happy with the camera auto white balance and darktable’s handling of it. However, I have had a few instances where very pure reds are rendered correctly in the OOC jpeg, but begin with a magenta hue in darktable. (I would have posted about this before, but the only obvious cases I’ve found are ad hoc cosplay pictures and I don’t want to post those raws)

I think it’s coming from the camera input profile. I’ve experimented with a lot of methods to fix that, and one of them had me make a custom CC preset only using the channel mixer. I think it works well, but I haven’t done much proper testing. You might not need it now, but I’ll upload it just in case.
channelmixerrgb_m6 maybe.dtpreset (1.1 KB)

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Your setting are correct. Makea preset using as shot to camera in the color calibration module.

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