Colour Balancing (with or without colorbalanceRGB module)

I’ve read a couple of articles about colour correction and colour balancing plus I have loaded up the colorbalanceRGB module so now I’m practically an expert, I just need a couple of hints and tips to finally crack it (that’s a joke by the way!)

Seriously though, I am interested in the ways people can develop the attached image. Its really a rescue job as the photo was taken in the poorly lit Cairo Museum, through glass. Is it possible to get good contrast, and vivid colours, especially the green?
Image was taken with Canon EOS R6 and converted from .CR3 to .DNG with the Adobe tool.
Image licence is Creative Commons.ER6_4097.dng
Here is my best attempt so far:


and the XMP: (8.7 MB) ER6_4097.dng.xmp (9.4 KB)

Change or add the Play Raw tag so that you will get more participation

Hi @Aliks,

I hope this what you are looking for? Or at least gives you some hints :wink: hope i didn’t over done it :smiley:
(i used a development version of darktable, so maybe you cannot use my xmp file :sweat_smile:)

DT 3.5.0+1303


ER6_4097.dng.xmp (18.7 KB)

Many thanks - no problem with the .xmp

Interesting, but its a bit difficult to follow your processing and see what is contributing to the overall image.

It looks like you have a few presets that may not be relevant (lens correction and velvia?) and although the green looks good on the coffin, it seems to be at the expense of a green wash in all the shadows.

Which modules did you tinker with most for the colours?

This is Photoflow, not Darktable:


ER6_4097.jpg.pfi (40.1 KB)

Adjustments are:
i) Set camera colour balance to D65 (6504K, 1.0 tint)
ii) Add a Colour Adjustment (slope/offset/power) and adjust the slope parameters for white balance (guessed that the back of the display case was neutral, and then reduced the red a bit because the colour looked better that way)
iii) Add a second Colour Adjustment to deal with the flare from the glass - set the offset to a negative number, increase the power a bit and increase saturation
iv) Adjust contrast to taste with curves.
v) Add some local contrast.

2 Likes

You got me there, my editing workflow is quite chaotic :sweat_smile:
I think the biggest saturations boot in my xmp are:

  • filmic rgb -> look -> middle tones saturation -> 40%
  • vibrance rgb -> +0,77
  • color balance -> contrast 14% + output saturation 104%
  • with color zones I boosted the greens on the coffin and muted the blue window reflection
  • the haze removal helps to fight the reflections a bit

The Velvia module is not necessary it was a test and I did forget to turn it off.
The lense correction module is on by default via a preset, but I think it doesn’t correct the image in your case? I guess, your Camera is not supported yet?

I am not sure where the green color in the shadow is coming from because i boot the greens with the color zones module and when I toggle it only the coffin greens change?

I hope this helps you a bit :wink:

ART

If possible and permitted, in those conditions, you have better to get your lens as close as possible to the glass.

Edit: new trial

The coffin is wooden with a painted surface but the wood itself is a warm pale brown, and in fact the background at the top of the picture is a similar hue. There isnt really anything neutral in this photo to give a white balance, but the camera opted for 2900K which is similar to other shots nearby where I could get a reading from a piece of white paper describing the object.

gaaned92 - good call on getting close up to the glass. I used that tip later on the same trip on the airplane for landscape shots. In the museum though, its a tradeoff between getting the whole object and getting glass reflections.

This was one of the worst shots I got, but it makes it interesting to see the tricks that help to recover. Perhaps this is a bit off topic for most dedicated DT users, but maybe the manual could expand to give a few hints/examples of good uses for each module?

Here’s my attempt using a mask for the green, some colourfulness and a few other bits and pieces. But the green fringe around the bright light needs sorting out.


ER6_4097-coffin-under-glass-rawconvert-V1-S-sRGB.xmp (48.8 KB)

I noticed this in the terminal window where I run rt -

[export_job] exported to /home/paulssd2/Downloads/ER6_4097-coffin-under-glass-rawconvert-V1-S-sRGB.jpg
[exiv2 dt_exif_get_thumbnail] /home/paulssd2/Downloads/ER6_4097-coffin-under-glass.dng: corrupted image metadata


ER6_4097.dng.xmp (8.2 KB)

1 Like

Thanks for posting, tricky shot
I tried to develop correctly hieroglyphs (at least my own interpretation of what should be the correct colors/contrast )
dt 3.4.1


ER6_4097.dng.xmp (14.8 KB)


cairo.museum.glass.pp3 (22.7 KB) RawTherapee 5.8 (Development)

Tricky indeed.

@Aliks: You asked for vivid colours, especially in the greens. I’m wondering how realistic that would be. This is a very old coffin (2000+ years at least I’m guessing) and those colours would have faded over time. I did add some pop to the colours, bit too much for my personal taste to be honest.

My try.
dt 3.4.1
Modern workflow. Slight tweaks in color calibration. Special attention to the reflection on the schowcase (tone eq). Color zones to tweak the green. Contrast via haze removal, local contrast, contrast equalizer and filmic contrast.

ER6_4097.dng.xmp (21.2 KB)

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Jade - Actually the green pigment is mineral based - crushed minerals with copper salts giving the intense green. I don’t think it fades much with time.

So I like your first image best - but as you say its a matter of taste.

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Ah, thanks for that info!

So basically a Malachite [Wiki] based paint, which is indeed lightfast. Still impressive that it holds out for over 2 millennia!

Green; The Egyptian colour of good, harmony, peace, death and rebirth.

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I never really know what to do with divide blend mode… I saw this and thought I would try it in DT with the colorize module …https://www.youtube.com/watch?v=eEaPq0aaDCU

I should try it in Gimp where it would be closer to Affinity…

Result with divide and colorize…will of course vary with hue , sat and opacity used…

seems a bit dark on import …maybe

Hmmm - could just be a little on the green side???

Are the colors like this one…I tried to find the piece on the internet for reference…this is not it but looks similar… image