ART 1.5: Camera-specific white balance presets

Software ART
1

One of the changes in ART 1.5 is described as “added support for camera-specific white balance presets”. When editing a .CR2 (RAW) file from my Canon EOS 80D, I see that the Color > White Balance > Method menu indeed contains “Camera preset” with choice of daylight, shade, cloudy, etc., and the results are excellent. OTOH, editing a .CR3 file from my EOS M6 Mark II, “Camera preset” is replaced by “Custom multipliers”. This was disappointing, for ART has treated .CR3 files very well in other contexts.

Further investigation led me to the file “wbpresents.json” in the root directory of ART. That file states that the included white balance multipliers for specified cameras are “generated from src/external/wb_preset.c of Darktable”. Since Darktable is incompatible with .CR3 files at present, I assume this is why ART is missing the corresponding “Camera preset” multipliers for .CR3. Is there any way to get the .CR3 multipliers other than experimentally taking photos under the various lighting conditions?

2

In principle, they should be in the exif data. But last time I checked exiftool couldn’t find them for cr3, and exiv2 doesn’t support cr3 at all. I might try again with a more recent version of exiftool, maybe things have changed…

3

Here are presets for the M6 mk II:

[
  {
    "make_model" : "CANON EOS M6 MARK II",
    "presets" : [
      { "name" : "daylight", "multipliers" : [ 1.7177734375, 1, 1.5302734375 ] },
      { "name" : "shade", "multipliers" : [ 2.0322265625, 1, 1.3056640625 ] },
      { "name" : "cloudy", "multipliers" : [ 1.8623046875, 1, 1.412109375 ] },
      { "name" : "tungsten", "multipliers" : [ 1.1640625, 1, 2.306640625 ] },
      { "name" : "cool white fluorescent", "multipliers" : [ 1.4501953125, 1, 2.169921875 ] },
      { "name" : "flash", "multipliers" : [ 1.9287109375, 1, 1.3984375 ] }
    ]
  }
]

You can put the above in a file $HOME/.config/ART/wbpresets.json and it should work. I will also add it to the global wbpresets, and will be available in 1.5.1

4

Thank you, Alberto. I sincerely appreciate your help.

Dwynn

5

Hello,

I’ve got a similar, but different effect with ART (Version: 1.20.1).
Images taken with the Pentax K-5II do have the camera presets for white balance and images taken with the Pentax K-3II don’t have that menu entry.

Both cameras are in the /usr/share/ART/wbpresets.json file with exactly the Model string from the EXIF data:

$ grep -A 12 -B 1 "$(exiftool -'Model' Pictures/Originale/20230701/20230701_110328.PEF |awk -F: {'print $2'} | sed -e 's/^ //')\"" /usr/share/ART/wbpresets.json
{
"make_model" : "PENTAX K-5 II",
"presets" : [
{ "name" : "daylight", "multipliers" : [ 2.13672, 1, 1.62891 ] },
{ "name" : "shade", "multipliers" : [ 2.55078, 1, 1.21484 ] },
{ "name" : "cloudy", "multipliers" : [ 2.30078, 1, 1.39062 ] },
{ "name" : "daylight fluorescent", "multipliers" : [ 2.63672, 1, 1.56641 ] },
{ "name" : "white fluorescent", "multipliers" : [ 2.26172, 1, 1.74609 ] },
{ "name" : "cool white fluorescent", "multipliers" : [ 2.05469, 1, 2.15625 ] },
{ "name" : "warm white fluorescent", "multipliers" : [ 1.71875, 1, 2.69922 ] },
{ "name" : "tungsten", "multipliers" : [ 1.26562, 1, 2.81641 ] },
{ "name" : "flash", "multipliers" : [ 1.85156, 1, 1.79297 ] }
]
},

and

$ grep -A 12 -B 1 "$(exiftool -'Model' Pictures/Originale/20230621/20230621_132851.DNG |awk -F: {'print $2'} | sed -e 's/^ //')\"" /usr/share/ART/wbpresets.json
{
"make_model" : "PENTAX K-3 II",
"presets" : [
{ "name" : "daylight", "multipliers" : [ 2.1875, 1, 1.57812 ] },
{ "name" : "shade", "multipliers" : [ 2.70312, 1, 1.16016 ] },
{ "name" : "cloudy", "multipliers" : [ 2.41797, 1, 1.33984 ] },
{ "name" : "daylight fluorescent", "multipliers" : [ 2.62891, 1, 1.51172 ] },
{ "name" : "day white fluorescent", "multipliers" : [ 2.23828, 1, 1.69531 ] },
{ "name" : "white fluorescent", "multipliers" : [ 2.01172, 1, 2.02344 ] },
{ "name" : "warm white fluorescent", "multipliers" : [ 1.69531, 1, 2.51562 ] },
{ "name" : "tungsten", "multipliers" : [ 1.32031, 1, 2.72656 ] },
{ "name" : "flash", "multipliers" : [ 2.48828, 1, 1.30859 ] }
]
},

I don’t get the reason for that different behaviour.
Any hints (perhaps I didn’t see it in the ART reference documentation or on Rawpedia) are appreciated.

Many thanks!

E.

6

That’s strange indeed. I’ll take a look

1 Like
7

Can I do something to help, eg. provide more specific information, the complete EXIF data of the images, images itself or similar?

Many thanks!

E.

8

Hi, if you can share a raw file that triggers the bug that would help indeed, thanks!

9

Hi,

here you are.

E.
20230623_124534.DNG (29.5 MB)

10

Thanks. It should be fixed now in the git repository. If you don’t want to build from git, as a temporary solution you can change this:

    "make_model" : "PENTAX K-3 II",

to this:

    "make_model" : "RICOH PENTAX K-3 II",

in /usr/share/ART/wbpresets.json until the new version of ART comes out.

HTH

1 Like
11

Thank you very much for your quick and helpful answer.

I tried the workaround in /usr/share/ART/wbpresets.json and it works not only for the images of the K-3II but also for the images of the K-S2.

You made the world a bit better. :slight_smile:

E.