I enjoy painting animals and have been asked by a friend to do a painting of his black Labrador.I am having a problem with the shine on his coat.I am using oils. can you help please?

I'll go along with Marie. Only use black for the very darkest shadows (and if you can, don't use a black out of the tube, mix one out of a good transparent burnt sienna and ultramarine blue) Colour is all relative and it will be dark enough. Having blue in the mix means that using blue to colour the highlights on the fur will be easier. Look carefully and you'll see that there's probably not as much black as you think.