SEE: Clarity, Color, Intensity, Legs
A wine's color is largely determined by the grape variety (in addition to its age). Red wines range from (darkest to lightest): purple » ruby red » garnet/brick » tawny/amber.
Color can also indicate the age and the health of a wine: A young red wine's color should be darker, rather than lighter, and may have a purplish tinge to it.
Over time, the color of a red wine evolves towards amber.