Do you know a site for colour creation?

Question

I had a problem recently. I must create a colour by another three. You know, put three colours and result a special one.

Answer 1

Er..... I have no clue what you mean...
But how about this:
http://www.colormatch.dk/
You can digitally mix any amount of three colors to get a new one.

Answer 2

Here is a link to the Munsell color system, the most widely used artists' colour-mixing tool

http://web.archive.org/web/20030813092028/www.adobe.com/support/techguides/color/colormodels/munsell.html

hope that helps