Any other color or combination of colors is a disqualification. A small white spot on the chest is permissible, but not desirable. White hairs from aging or scarring are not to be misinterpreted as brindling. Blacks are all black. A black with brindle markings or a black with tan markings is a disqualification.
Chocolates can vary in shade from light to dark chocolate.
From The Official AKC Standard of the Labrador Retriever . Phenotype can therefore be defined as the actual color appearance. However, when one breeds two black Labs, one may get only black puppies, but upon breeding another two black individuals one may get yellow and chocolate puppies as well as black. This indicates that though the dogs from two such crosses may appear to be the same color, or phenotype, they don't have the same genetic makeup, or genotype . It is the genotypes of the sire and dam which are responsible for yielding color variations in a litter.