Colour Balancing (with or without colorbalanceRGB module)

Yes those colours look good to me. The green is probably a malachite mineral colour, and the wood colours are nut brown.

The other distinctive feature of my sarcophagus image is that the colours have an attractive “sheen” as if there was a layer of varnish on top of the paint/pigment.

I’ve looked online for the exact image but drawn a blank. I didn’t make a note of the labelling so I cant give a definitive reference.

I saw that (sheen) in many of the images. I bet that would be hard to replicate…

Sheen may be hard to replicate in regular processing. E.g., think of gold colour vs actual gold.

The particularity of metals (e.g. gold) is that the specular reflections take the tint of the metal (yellowish in the case of gold, reddish for copper, …), whereas for non-metals the reflections are not coloured. In the case of varnished metal, you can get a coloured reflection from the metal, layered with a non-coloured reflection from the varnish.

Those effects are well understood for generated images. In photography, it means you should not force reflections from (bare) metal to be neutral.

And application of varnish after the colours is still a common technique to get a consistent surface texture, and to protect the decorations. It’s one of the reasons the colours stay “fresh”, helped by the storage in dry, dark, conditions at fairly constant temperature for most of the last 2000-3000 years.

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Interesting.

I thought it couldn’t possibly be the effect of a varnish as varnishes tend to darken and discolour over time. However, a little googling shows that the dynastic Egyptians commonly used beeswax based varnishes. . . . .

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Found this page, maybe it helps (Pic # 3 from above).

MATTHIAS SCHNEIDER : FOTOGRAFIE · ÄGYPTEN 2017 – Museum Cairo

Fantastic, that is indeed the same sarcophagus - you can see the same damage marks.
The text in German is useful , but I can find no other references to the name Djedhoriufanch - presumably a relative of Djedhor. Is that a German form of the name maybe?

I have plans to go back to Cairo after lockdown, so I will definitely take some more pictures and do some better labelling.

The text says that Djedhoriufanch was a priest, the highest administrator of the sanctuaries of Amun-Res.

Good light for your next pictures in egypt :wink:

Hello:

Here is my attempt to develop your image.

ER6_4097.dng.xmp (15.3 KB)

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Yes got that, but its strange that there is no other mention of Djedhoriufanch on the Internet (or at least not on my google)

Djedhorefankh

https://www.google.com/search?sa=X&sxsrf=ALeKk00u1GOGjmj3zYK0pIC2mAAy_a1gqw:1615925599121&source=univ&tbm=isch&q=Djedhorefankh&hl=es-419&client=ubuntu&ved=2ahUKEwiBmsb6z7XvAhVKlVkKHVsoDmkQ7Al6BAgHEAs&biw=1689&bih=1191

Franklin,

Yes that is the Anglicized name - looks like National Geographic did an article in 2017 on Djedhorefankh (or Tchet-Heru-af-anch). The Cairo museum has so many articles in its basement, I am looking forward to seeing the new museum out in Giza (whenever it opens.

And your take on the image is pretty good too - balancing all the defects of the raw image to get a nice output.

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ER6_4097.dng.xmp (39,9 Ko)

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Thanks Aurelien!
I notice that you used the Color Calibration module to improve saturation and selectively brighten the greens. Do you prefer this module over Color Balance and Color Zones?

Will your dev module Color Balance RGB become the preferred option when it is released?

My attempt with RT 5.8-dev
Hoping to get the color right with CIECAM16:


20210311_ER6_4097.jpg.out.pp3 (14.4 KB)
Edit: Link to CIECAM16

Well, here it’s not so much a matter of saturation rather than reconstructing the signal. The glass here behaves like a green filter, so the color calibration was used to mostly to undo the filtering. Then, if you increase the colorfulness a lot, you tend to darken the picture, so the green brightening was just to compensate.

Yes, it’s much more robust.

It depends for what purpose, but I really don’t like color zones. The hue masking is brittle and you don’t get a lot of margin until you start creating chroma noise.

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ER6_4097.dng.xmp (13.1 KB)

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