Dar Scott dsc at swcp.com
Wed Oct 9 17:32:28 EDT 2002

On Wednesday, October 9, 2002, at 03:32 PM, Dan Friedman wrote:

> Does anyone know the algorithm to get a "Lighter" version of a RGB value?
> For example, if you have a RGB value of a shade of Green (0,176,23), and
> you
> want a version of this color that is 25% lighter (ie 25% more white).
>
> Any thoughts?

Maybe you can mix it with white.

Assume a color RGB vector, then...

lighterShadeOfGreen = (1-x) times shadeOfGreen + x times white

where x is, say, .25

This will move the color 25% of the way toward white, I think.  This would
be in a straight line in RGB space.  I have no idea whether this is
equivalent to what Sarah suggested.  The two methods might take different
paths to white for all I know.

(The product of a number times a vector is the vector with each component
multiplied by the number.  In terms of the RGB color this means taking each
of R, G and B and multiplying by the number.  To add two vectors, add the
components.  When arithmetic is all done, round each R, G and B to a whole
number and limit to the 0 to 255 range.  If you need several colors, do all
the calculations and then round.)

Dar Scott