A chocolate dog will be solid chocolate brown. Chocolate can be varying shades of brown reminiscent of confectionery, ranging from the lighter brown of milk chocolate to the medium brown of semi-sweet to the deeper brown of dark baker's chocolate. Chocolate dogs have self-coloured pigment in liver/brown instead of black for eyerims, lips and nose. There is no black on a chocolate dog at all.
Note: The eyes of a chocolate are generally lighter than those of a black pigmented dog , ranging from medium to light brown or occasionaly dark amber.
Chocolate also comes in many of the comparable colours to what is found in black pigmented dogs, such as Chocolate & Tan, Chocolate Sable etc. For all of these, the dark portions of the coat will be chocolate, and the pigment will be liver/brown.