38 Werner has shown the rgb-syntax to mix colors, egreg has shown how to define a color in RGB and then use it. If you want to specify a color with RGB values [0-255] without defining it before, you can use the rgb-syntax Werner has shown by setting the optional div-parameter to 255 (see xcolor package documentation, pages 13 and 16).
tikz pgf - How to specify a fill color in RGB format in a node in ...
I would like to check if a color is defined either passing the RGB numbers or a colorname to the key categoryColorPrimary / categoryColorSecondary. Using xstring doesnt feel right and I need to expand the argument.
How can I check if a color is defined using (RGB) numbers or a name?
The color package also supports decimal values in the RGB color model that accepts integer values in the interval [0,255]. On the other hand, xcolor offers much more features, so it's better to use it.
There is a straightforward solution to this problem, implied by section 114.1.1 of the pgf/Ti k Z manual and illustrated in Gonzalo Medina's answer and this is to load xcolor with option rgb or passing rgb to the package as a global option. However, I'm using the colour series in a package and I don't want to force rgb on the user globally. So I think it would be better to use ...
I tried to specify a RGB color in a color box in this way, but it doesn't recognize RGB, only rgb that is a different thing. How can I specify a RGB color in a color box? \documentclass{article} \