Black is the breed’s default
Black is the dominant colour in the Border Collie, which is exactly why black and white is by far the most common coat you will meet. Genetically a black dog carries B/B or B/b at the brown locus with full pigment — the final step of pigment production runs to completion and the eumelanin stays jet black.
In the coat, black should read as a deep, true black, though in sunlight you may catch a hint of blue or brown cast depending on the recessive genes hidden underneath. Pigmented areas — the nose leather, eye rims and lips — should be solidly black.
Eye colour on a black dog
Eye colour has a lot to do with the recessive colour genes a black dog carries. On black Border Collies the iris can range from dark brown through medium brown and hazel, and occasionally sky blue. None of these are faults of the black itself — they simply reflect what is waiting in the background.
