"Charlotte E." wrote in message
I stumbled across this nice one:
http://gauth.fr/2011/09/get-a-color-...b-combination/

Very neat indeed :-)
But made in JavaScript, which I know virtual nothing about...

I was wondering, if anyone has made something similar in VBA?
Can it be done?
How?

I did but it was a long time ago. At the time I couldn't find any examples
had despite extensive searching. Originally it was VBA but I put it in a VB6
ComAddin, a colour match tool as a small feature of a much larger range of
colour related stuff for Excel. Briefly this is "how" to go about it.

First you need a swatch of defined and optionally "named" RGB colours to
match against, your example seems to be using this list of named and defined
colours -

http://gauth.fr/2011/09/get-a-color-...b-combination/

But there are others, not least the well known swatch (1100+ colours) from a
certain print ink producer, or say the 140 named html colours.

The hard bit is to define a virtual "colour space" that reflects the very
different way the human eye perceives colour differences vs the actual RGB
differences. Eg the eye perceives green as occupying a much larger relative
space than its neighbour in the spectrum cyan. There are various example
spaces out there but replicating them is difficult. I gave up and devised my
own colour space as a semi regular 3D space, complex but regular enough to
be defined with an algorithm.

Then map all the colours in the list in the space with XYZ coordinates from
a given reference point, and similar with the RGB you want to match. Finally
the simple bit, calculate all the 3d distances of your colour to match to
each of the mapped swatch colours. The best match is the one with the
shortest distance in the space, though in a large swatch a good idea to
return and rank a few other close matches and let your own eye judge the
best. And that's all there is to it!

Regards,
Peter T