On Mon, Jun 29, 2009 at 9:33 PM, Martin Nordholts<ense...@gmail.com> wrote:
> Maybe the RGB -> HSL conversion is buggy?

I don't see it as a bug... it's more of a problem. Gimp uses HSL(?)
and PhotoShop /seems/ to use CIELAB for these operations.
This effects all layer modes that uses that color space for
conversions and doesn't work in the same way as PS... Hue, Saturation,
Color and Value.

HSL treats pure yellow by giving it the same lightness as pure purple.
CIELAB treats them more from a human perspective and sets the pure
yellow to be light (lightness) and pure purple as dark.

Helpful tool to visualize it: http://www.cs.rit.edu/~ncs/color/a_spaces.html

I think we need to add conversion tools for the color space and
rewrite those routines (or add new ones) if it should be a goal to
correctly import PS files with layer modes. (This could actually be a
good way to learn some more about the gimp code for me)

Any comments on this?
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