For some of you developers out there, this is surely old news. But I thought this to be rather illuminating to the layman among us. And by “us”, I mean “me”.
Computer Color is Broken
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Not so sure about that - maybe more developers should be aware of the option. Not sure. There is lots of software around.
John
I would be surprised if at least something wasn’t known about this. I remember reading about it a few years back in a Photoshop class I had to take, blech. I only thought about it again when this video came up in my YouTube feed.
Now, how to go about implementing fixing it is, I’ll grant you, another story.
There’s an article on Nine Degrees Below talking about which operations need to be done in linear space, and which in perceptual space.
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This has already been addressed in GIMP master.
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So does it automatically switch into a linear-gamma version of SRGB for those operations that require it for correct maths?
I assume this doesn’t happen when using darktable, as it mostly works within CIELAB, which is perceptually uniform?
“Is your image editor using an internal linear gamma color space?” has tests for checking whether an image editor is or isn’t silently linearizing the RGB values for selected editing operations and blend modes.
The tests are simple and you might be surprised at the results you get with different image editors. In GIMP-2.9 try the tests at linear light and also at perceptual gamma precision. In PhotoShop, there is a setting in the color management dialog that affects results, and also the bit depth (32f vs 16i) makes a difference.
The article also considers whether an image editor “should” linearize RGB values. It’s not a cut and dried choice, there are trade-offs.
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