TrueType fonts are monochrome.
Colour effects can be achieved with care by overlapping the same text from several fonts of a collection of fonts designed for colour work.
For example the following set from P22 from the http://www.p22.com/Lanston/ section of the http://www.p22.com webspace.
http://www.p22.com/lanston/products/jacobeaninitials.html
http://www.p22.com/lanston/Jacobean.pdf
For example, my own Galileo Lettering collection of fonts and Chronicle Text collection of fonts.
Hopefully font technology will develop so as to have chromatic fonts.
One idea is my suggested eutofont format.
I have not done any more with the eutofont format since, yet I am hoping that it may get taken up some day.
William Overington