Color Values
Most markup, such as RealText and RealPix, can use color names and hexadecimal values for color attributes. SMIL 2.0 supports the color values defined in the Cascading Style Sheets 2 (CSS2) specification, letting you use RGB values as well.
http://service.real.com/help/library/guides/realone/ProductionGuide/HTML/htmfiles/colors.htm