Terence Jordan wrote:
>How can I control the lightness/darkness of a color picked from the color wheel?

Also, how do you accurately subtract one color from another?
More precisely, how do I compensate colors for a gray (or other light 
colored background?

For example, I have a color that was sampled with a digital camera or 
video camera.  The gray background should be white.  How can I adjust 
the colors (brighten?) to compensate for the gray background?
I assume the same correction that convert the gray to white could be 
used to correct the colors.

I've tried some simplistic approaches and quickly realized that some 
corrections would cause one or two of the component colors (r,g, or b) 
to either exceed the allowable value range of 0 to 65535.

Right now I just cap the values with:
if r&>65535 then r&=65535 and 
if r&<0 then r&=0

-- 
Pierre A. Zippi
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