Re: [Gimp-developer] Attempt to summarize the discussion of my examples of what doesn't work in unbounded sRGB

----- Mail original -----
On 04/21/2014 04:47 AM, Teo Mazars wrote:

----- Mail original -----

Similar issues are easy to demonstrate with Levels upper and lower
sliders, Gradients, Invert. These really need to be linear light

Is there a list of the operations that don't currently use linear

Yes, grep for "R'" or "Y'" in the operation directory.


But... are you really saying that Gradient should be implemented
using a non-perceptual color space?

Yes, to be technically correct.


I think gradient is a good simple example. How this operation
should be implemented exactly?

We want people to be able to draw perceptually linear gradient right?

I completely agree with you that people should be able to draw a
gradient in a perceptually uniform color space if they want to.

But any such gradient is not technically correct. Colors don't mix
properly in the almost perceptually uniform regular sRGB color space.

So any color mixing in the regular sRGB color space is technically
incorrect. For example, you get dark lines at the edges of soft brush
strokes. The same thing happens with gradients, except the darkening
artifact is spread out across the gradient and so doesn't look as
obviously technically incorrect.

Hmm, I understand, then the default black-to-white gradient would be non perceptually linear, which is more 
surprising than the color-to-color gradient. I think I am now convinced this is correct, but it will probably 
be puzzling to use. 

BTW, "gradient" is not such a good example because it's not related to chromaticities, "Invert" would be a 
better one.

[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]