Standard Colors
As stated in the AKC standard, there are three main colors: black, blue merle, and sable (ranging from golden through mahogany), marked with varying amounts of white and/or tan.
In all cases, the nose color should be black.
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 severely penalized to eliminate them from conformation competition effectively.
Disqualification: Brindle
Read about the DNA behind colors here.
Ranging from gold to mahogany with varying amounts of white.
Black with varying amounts of white and/or tan.
Gray and black with varying amounts of white and/or tan. The marking gene dilutes the basic black to a silver-gray, leaving patches of black in random areas. This is what is referred to as merling.
A bi-blue is the same as a blue merle except it has no tan markings.
Black with varying amounts of white and no tan anywhere on the body.