[Gimp-user] finding and replacing all variants of one colour

[pbw <forums gimpusers com>]

Virtual external house painters allow you to paint an image from a set of colour
swatches.  The best ones that I have seen seem to be able to replace the colour
while keeping the details and the variations in image colour due to differences
of light and shade.

I would like to be able to do something similar in Gimp. Starting from a base
colour point, select estimate colour variations based in differences in incident
light, and collect select this set of colours.  Then replace those colours with
a new base colour, applying the same incident light variations to the new
colour.

Do you have any suggestions for a basis in existing tools for achieving this?

-- 
pbw (via www.gimpusers.com/forums)