Wrong White Balance with the OM systems OM1mkII

Software RawTherapee
1

RT 5.11 appimage on opensuse leap 15.6

The white balance does not work properly.

The camera is set to daylight: 5300 and RT reads it at: 11346k.

camera-white-balance_2024-10-31_06-43-25
camera-white-balance_2024-10-31_06-43-25868×975 69.9 KB

the RT meta exif says: 5300k (at the bottom)

meta-exif-wb-2024-10-31_06-45-06
meta-exif-wb-2024-10-31_06-45-06614×1040 57 KB

and exiftool says:

 $ exiftool north-vancouver-shipyards-20241017-7356.orf|grep -i white
 White Balance 2                 : 5300K (Fine Weather)
 White Balance Temperature       : 5300
 White Balance Bracket           : 0 0
 Raw Dev White Balance Value     : 0
 White Balance                   : Manual

the files orf + pp3 are at:

 orf ==> https://drive.google.com/file/d/1knwwho1tTAG8_Uxs25_q8Sd_wQ182L80/view?usp=sharing
 pp3 ==> https://drive.google.com/file/d/1CBYAczd4_ASIahv0SdYsJE13dlFwDhha/view?usp=sharing

The problem for me is that I want to warm up the image from 5300k to 8000k to make it more light and airy. With RT, I have to go to the 60000k (max on the RT) and that’s not enough.

BTW, ART and DT work fine.

Is this a bug or am I doing something wrong?

Thanks

2

It’s probably just lack of support for this camera. I will take a look. Sorry for taking so long to respond!

3

The color matrix is missing for this camera. Until 5.12 is released, you can add this in your camconst.json. Be sure to add a comma to separate each camera entry if you have another camera in the file.

{
    "make_model": "Olympus OM-1MarkII",
    "dcraw_matrix": [ 9488, -3984, -714, -2887, 10945, 2229, -137, 960, 5786 ]
}

If you have never created such a file, then simply create it and add the text in this example.
~/.config/RawTherapee-AppImage/camconst.json

{
  "camera_constants": [
    {
      "make_model": "Olympus OM-1MarkII",
      "dcraw_matrix": [ 9488, -3984, -714, -2887, 10945, 2229, -137, 960, 5786 ]
    }
  ]
}

Alternatively, you can disable LibRaw in Preferences > Image Processing tab > Raw Decoder > Use LibRaw. dcraw recognizes the make as OM Digital Systems (instead of Olympus) and has a color matrix for it.

4

Thanks

5

I’m using rawtherapee 5.12, and I’m seeing a similar problem with the temperature slider. With an image taken with WB 5500K, I’m seeing 44727 in the temperature slider.

Screenshot from 2025-09-05 20-28-17
Screenshot from 2025-09-05 20-28-17493×665 35.2 KB

Let me know if you’d like a sample image to test with.

This is also with the OM-1 Mark II.

6

I’m using appimage version of rawtherapee 5.12, on an Ubuntu 24.04 system.

7

I tried creating the camconst.json file as shown, and it had no effect. Then I tried disabling libraw, and now I see a more reasonable colour temperature. In a file that shows 5300 in the exif data, rawtherapee now shows 5100.

I wonder if there is an issue with the make of the camera? Mine shows up as “OM Digital Systems”, not “Olympus”, in the Manufacturer field of the exif data. I tried using “OM Digital Systems OM-1MarkII” in the camconst file, but it didn’t help.