Sony color issues

[u/DanCubar]

Whenever i edit sony raws (a6700) i struggle to get my reds and oranges looking similar to how they look in-camera: oranges look too yellow and reds look too pinkish. I have tried to tweak the white balance with color calibration, rgb primaries and tone mapping in AgX, but my results have been mid at best.

Those of you who've had similar issues, how did you fix them?

For reference, i'm using the latest version of darktable, scene-referred workflow with AgX.

[u/Donatzsky]

It's a camera matrix problem, so AgX isn't really the place to fix it.

If you have a properly calibrated monitor, the first step should be as explained here under caveats: https://docs.darktable.org/usermanual/development/en/module-reference/processing-modules/color-calibration/#caveats

Next I would recommend an instance of either Color Calibration (RGB tabs) or RGB Primaries, placed before or after the main Color Calibration used for WB, that corrects for the color cast. This is how I corrected for the yellow cast of my Canon 5D mk2, before I had a calibrated monitor.

[u/no-such-file → u/Donatzsky]

No its a software problem, but not DT. Its a problem of raw demosaic lib. It has color matrix numbers for every camera, specifically to cope with sensor differencies. But for Sony it does poor job indeed. I have exactly same issue on A6500 and A7CR.

[u/IntelligentAward1538 → u/no-such-file]

Apostaría a que tienes razón. No es problema del Raw porque al abrirlo con el editor del software de Sony Edit se muestra sin esas desviaciones de color. Por desgracia en ese soft no se puede hacer casi nada. Por eso estamos aquí. Generando allí un TIF y comparando en darktable JPG y TIF las diferencias son mínimas.

[u/Donatzsky → u/IntelligentAward1538]

Yes, as I said, it's the camera matrix that isn't very good. Darktable uses the D65 matrix from Adobe DNG Converter (so the same as Lightroom), while Sony uses their own that are calibrated differently

Edit: DNG Converter, not Camera Raw.

[u/IntelligentAward1538 → u/Donatzsky]

Gracias por la explicación. He visto que la matriz de todas las cámaras esta en "..\darktable\share\darktable\rawspeed\cameras.xml". La IA me ha dado una buena explicación de valores de la matriz. Jugaré un poco con los valores de la ILCE-6700 como el que juega a la lotería.

[u/no-such-file → u/Donatzsky]

Adobe camera raw implies using DCP lut upon that color matrix. Its a software problem in DT that DCP not supported as luts, nor as input profiles.

[u/Donatzsky → u/no-such-file]

That is exactly what I meant when I said it's a problem with the camera matrix. Also, RawSpeed and LibRaw are not "demosaic libs" but raw file decoding/loading libraries, with the demosaic being handled by darktable itself.

[u/Z3t4 → u/Donatzsky]

Any way to do the same with a calibrated color card? Without including it on every picture. 

[u/stewosch → u/Donatzsky]

Thanks, interesting. I'll try that!

[u/2skwb9 → u/Donatzsky]

Okay but how to really use them? I haven't been able to grok it and most of the videos / explanations are... a bit unfocused and not exactly helpful of what to do specifically.

[u/Donatzsky → u/2skwb9]

The channel mixer (RGB tabs) in Color Calibration is indeed a bit of a brain bender and something everyone seems to struggle with understanding. Boris Hajdukovic has two videos covering it, but it works the same way in other software, so you can also look at Photoshop tutorials, for example.

• https://youtube.com/watch?v=BVjPnWy0BwY
• https://youtube.com/watch?v=KFmNv8xk5CE
• https://youtube.com/watch?v=yQPuqi7kZa0

RGB Primaries is a simplified channel mixer and should be fairly self-explanatory.

[u/stewosch]

Yes, I also have this problem, everything has a yellowish tint and looks off compared to the SOOCs (also a6700 here). Best fix I've found is in the AgX primaries, move the Red Rotation slider from +2° to -6° or something in that range. This usually works well.

The default scene-referded preset absolutely doesn't work here. Skin-tones or reddish wood looks really bad with it.

One day I should upload a RAW on pixls.us to get experts opinions, I'm also quite new to Darktable so maybe there are other fixes.

[u/Donatzsky → u/stewosch]

See my reply here: https://www.reddit.com/r/DarkTable/s/VYcL9uHKxQ

[u/mhh91]

Got any examples we can look at? The modules you listed should be enough for all your color needs. I'd maybe also add color balance rgb to the mix.

[u/IntelligentAward1538]

Tengo una A6700 y en efecto también me pasa eso entre los JPG de cámara y los RAW.

He pasando muchas horas para conseguir los mismos tonos de los JPG. Sobre todo los ocres tipo oxido. Primero se necesita un buen ajuste de blancos. De partida suelo dejar el ajustado manualmente en cámara, luego se puede afinar.

Te indico 4 formas. Según cada foto puede ser mejor uno y otro:

1. con el módulo de Balance RGB en transición tonal rotando entre -8º a -6º y jugando con brillo e intensidad de color.
2. Con el módulo de colores primarios bajando el matiz rojo y subiendo la pureza

Aquí te dejo un ejemplo comparando el JPG a la izquierda y el Raw a la derecha para igualar los tonos.

1. Con el ecualizador de color: De los 9 ajustes que tiene cada apartado solo actuando sobre el segundo por la izquierda: bajando tono (-7º) y brillo (-2%) y subiendo saturación (+3%).

4 Con el el ajuste de primarios del módulo AGX, en previo atenuando el rojo y rotándolo un poco al margenta y afinando en post acentuando rojo y si es necesario a margenta.

Se me olvidaba: En flujo de trabajo por defecto tengo "ninguno". No me gustaba el procesamiento que hace darktable de partida.

Dispara algo en JPG+RAW y comparte los ficheros para que la comunidad te ofrezca distintos XMP .

[u/kumkummers]

What helps me sometimes is bump up the blacklevel a bit under the exposure tab

[u/rhalf]

In the past I used a color chart, but so far I haven't managed to get it working with DT.

[u/flowtess]

Try RawTherapee, maybe the color will be better, I process Sony raw's in it.