The command ribcolor sets ribbon color. Even if only particular atoms are specified, the ribbon segment(s) corresponding to the entire residue(s) containing the atoms will be affected. Using ~ribcolor sets the ribbon color to none (no color assigned).
Color_name can be a built-in name or a name defined previously with colordef. In addition, colorpanel or fromeditor can be used to indicate the current Color Editor color.
Color sets per-atom colors and modelcolor sets colors at the model (or submodel) level; surfcolor sets which level is used as the source for visible surface colors. Rainbow sets both per-atom colors and per-residue ribbon colors.
See also: ribbon, color, modelcolor, rainbow, rangecolor, the Actions menu