Re: [Gimp-developer] Documentation on color spaces

[Simon Budig <simon budig de>]

Elle Stone (l elle stone gmail com) wrote:
> In the meantime, if anyone would like to read it and give feedback,
> corrections, suggestions, I'll edit the Guide to make it more clear,
> more useful, etc (if nobody is interested, that's OK too!).

I think it is very helpful. I've been dabbeling with colors some time
ago (trying to improve the color reproduction of a network camera) but
did not dive into the "profiling" area.

Some remarks:

In section B3 I had trouble following, because having five XYZ
coordinates to specify a RGB cube (with - as you claim - additive light)
seems over-determined. It is not clear how RGB(1,1,1) - i.e. additive
RGB(1,0,0) + RGB(0,1,0) + RGB(0,0,1) results in the specified white
point. The same problem is there with the black point. *if* this stuff
is additive, then black always will be the absence of R, G, B, i.e. a
pitch black XYZ(0,0,0). So there is a dragon lurking when claiming
additivety.

Another (slightly philosophical) issue for me is, that you never explain
what you mean by color. You write that "every real color (that is, every
color out there in the world, that humans can see) has a unique
location".

It might be worth noting, that this is different from looking at color
as "a specific intensity-distribution of wavelengths". There are
different intensity-distributions that map to the same XYZ coordinate.
While a person with normal eye-sight perceives these two
"intensity-distributions" as the same color (and for these purposes XYZ
is perfectly OK) a person with a color vision deficiency might be able
to keep them apart -
  see e.g. http://en.wikipedia.org/wiki/Colorblindness#cite_note-5

I am not sure if mentioning this helps or if it confuses stuff...  :)

Bye,
        Simon

-- 
              simon budig de              http://simon.budig.de/