Depends entirely on what other colours are carried by the parents - you can't give a definitive answer without this knowledge, sorry. If the two blacks carry no other colours as recessives, then all pups will be black but if both parents carry recessive colours like red/liver/and tan, then these colours could be produced (but both parents must carry the recessive gene for the particular colour). Two black parents can also produce particolour pups but again both parents must carry the recessive particolour gene.
