As stated in the standard: Black, blue merle, and sable (ranging from golden through mahogany); marked with varying amounts of white/and or tan.
Faults: Rustiness in a black or blue coat. Washed out or degenerate colors, such as pale sable and faded blue. Self-color in the case of the blue merle, that is, without any merling or mottling and generally appearing as a faded or dilute tri-color. Conspicuous white body spots. Specimens with more than 50% white shall be so severely penalized as to effectively eliminate them from competition.
Read about the DNA behind colors here.