[comp.graphics] A Color Mixing Question

flanery@mips.COM (Mike Flanery) (11/21/90)

I have recently written a "color editor" for X that allows the user to
"mix" colors using various different color models (rgb, cmy, hls,
hsv), but what I really want to do is create an interactive palette
that would allow the user to mix colors in a manner similar to an
artist mixing paints on a palette. I found a reference to "tristimulus
values" for colors and how a mixture of colors can be calculated from
their respective "tristimulus" values based upon proportions. But,
there was no explanation for determining tristimulus values from what
I am accustomed to working with: machine rgb values. 

Can some of you graphics/physics/color gurus out there shed some
(white) light on the issue of color mixing?

You can send me email, or post a reply.

Thanks.

*************************************************************************
****  Michael Flanery, Systems Engineer   ****                       ****
****  Mips Computer Systems               ****                       ****
****  (Dallas Field Office)               **** "Shave the cheetahs"  ****
****  214-770-7979                        ****                       ****
****  flanery@mips.com                    ****                       ****
*************************************************************************

curts@usenet.umr.edu (Curt Schroeder) (11/29/90)

In article <43457@mips.mips.COM> flanery@mips.COM (Mike Flanery) writes:
>
>
>I found a reference to "tristimulus
>values" for colors and how a mixture of colors can be calculated from
>their respective "tristimulus" values based upon proportions. But,
>there was no explanation for determining tristimulus values from what
>I am accustomed to working with: machine rgb values. 

Tristimulus values are used in regard to spectral sensitivities of image
sensors (including the human eye).  The Tristimulus or Standard Observer Curves
are the result of a large number of color-matching experiments performed by
many observers and have been averaged and processed to create the curves.  I am
getting my information from _Robot_Vision_, by Berthold Klaus Paul Horn, MIT
Press, 1986.  He has a few pages on the subject.

Curt Schroeder

=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
|  Curt Schroeder                      | curts@ee.umr.edu       |
|  University of Missouri - Rolla      | curts@cs.umr.edu       |
|  Electrical Engineering Department   | s076895@umrvma.bitnet  |
|  Rolla, Missouri  65401              | -- Apple II Forever -- |
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
| "Oops?  What do you mean, oops?  I distinctly heard an oops!" |
|      - Opus                                                   |
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=