W3C home > Mailing lists > Public > www-style@w3.org > June 2012

Re: [css4-color] unclamped values for RGB

From: Alan Gresley <alan@css-class.com>
Date: Mon, 18 Jun 2012 12:43:58 +1000
Message-ID: <4FDE95EE.7070802@css-class.com>
To: Rik Cabanier <cabanier@gmail.com>
CC: www-style list <www-style@w3.org>
On 18/06/2012 5:18 AM, Rik Cabanier wrote:

> The problem I see with the current spec, is that it is wrong and that it
> will make decent color management in the future impossible. CMS is
> primarily about mapping gamuts from one colorspace to another [1]. By
> removing the clamping, the gamut is made infinite so this becomes
> impossible.
> I think if CSS implements the SVG color-profile property [2] (without the
> <name>  keyword), that would be a great step forward. Old implementations
> would ignore it, so their colors will look slightly off but would most
> likely still be reasonable.
> Lab would be really great since it corresponds to how we perceive color.

Are you referring to CIELAB [3]?

Also, the way we perceive color is not fully understood by academia (nor 
by myself). Please view this test.


Firstly, 'example 1' is very large representation of 'example 2'.

In 'example 3' (which is identical to 'example 2') one can perceive on 
the left of this whitish (since it's over black) region a red band and 
then a yellow band. With the same example, one can perceive on the right 
of this whitish region an aqua blue band.

Here is a photograph of this whitish region of 'example 3'.


How is this possible?

> This makes gradients and meshes more pleasing to the eye and has no need
> for profiles from the user's side.
> It's not unthinkable that in the near future there will be a race for best
> color displays (like there now is for resolution) so it would be good to be
> prepared.
> Rik
> [1] http://en.wikipedia.org/wiki/Color_management#Gamut_mapping
> [2] http://www.w3.org/TR/SVG/color.html#ColorProfileProperty

This is my major concern. A race for the best color displays (along with 
some specs or standards) where perception of color is not understood (or 
understood in terms of the 'classical theory of light').

I once stated on this mailing list that color could be generated by use 
of nanometers [4]. For this to even be done, it needs to mapped 
correctly to RGB colorspace.

3. http://en.wikipedia.org/wiki/Lab_color_space
4. http://lists.w3.org/Archives/Public/www-style/2010Sep/0488.html

Alan Gresley
Received on Monday, 18 June 2012 02:44:29 UTC

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