A few additional notes … the following applies only to the 3D labels:
color orange,r,l (meaning coloring ribbons and labels only)
… and if you didn’t put any modifiers right after the color name (example: color orange :.R) it would color all types of things, including atoms, ribbons, labels, surfaces … of chain R in that specific example. If you are using 2D labels, you can change their colors however you like by clicking on the square color well in the dialog and then using the Color Editor. <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/colortool.html> The Color Editor has sliders, but alternatively you can enter any hex color code or a built-in color name. You can also change 2D label colors with the 2dlabel command, but it is usually easier to deal with 2d labels interactively. Elaine