"Bald Eagle" <cre### [at] netscapenet> wrote:

> It's early, and the coffee is still sinking in, so I don't fully understand why
> gamma gets applied to an image in the first place - unless it's just a way to
> preserve the original gamma=1 color values for image-editing purposes.
>

That is the core, or origin of the problem. In the early day it seemed wise to
safe files "gamma encoded" so they didn't need that process every time they put
an image on screen. It save clock cycles.

But when you operate on them you first have to go back to linear. But, but, we
didn't even know from what gamma we had to go to linear.... as no format stored
any metadata and Apple did it different any way. (PNM uses BT.709, but now often
srgb...). Even Adobe (Photoshop) did it wrong and happily operated on non linear
data.

For me, in POV-Ray, for a single data point this srgb is a non-issue. "One
tweaks a colour anyway". For importing images as texture it is a different
issue, but there also, tweak the image data to your desire to fit the scene or a
proper reference. I wouldn't miss srgb.


ingo

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