Re: [Gimp-developer] Some blend modes break in unbounded mode sRGB

[Elle Stone <ellestone ninedegreesbelow com>]

On 04/13/2014 11:26 AM, Gez wrote:
> El dom, 13-04-2014 a las 00:45 +0200, Øyvind Kolås escribió:

> I think that what Elle is asking is about the RGB operations that break
> with ubounded sRGB chromaticity values. Several operations don't seem to
> be suitable for chromaticity values beyond the 0,1 range.

Yes, some operations break because they weren't designed to work with 
RGB values less than 0 or greater than 1.

But even if the image is clipped to the sRGB color gamut such that no 
RGB values are less than 0 or greater than 1, forcing the conversion to 
sRGB rearranges the channel data radically, depending on the source 
color space and also the image color gamut. Consequently fundamental 
editing operations like Channel Mixer and channel blending no longer 
work as expected.

And even if the image is clipped to the sRGB color gamut, the results of 
divide, multiply, lighten only, darken only, hue, saturation, color, 
value, etc are altered by the conversion, and not in a good way.

Elle