Did you use pastels?
it's mixed media - most of my work tends to be
I started off underpainting in watercolour to get the different colours underlying the black - I mixed just burnt umber and ultramarine(blue), which make a black that you can tip towards blue or brown and a touch of cerulean blue for the parts where the light caught his fur. Oh and of course his eye colours and then background was a wash of burnt sienna very thin and mottled with white chalk pastel scribbled over it.
Then when it dried, I used charcoal to draw into it and I scratched into the paper with a craft knife to lift the thin highlights and where the light caught his black whiskers against his black fur.
I think that's all - I never plan exactly what I'll use in advance, I just pick up whatever will take the image in the way I want as I need it.
I like the different kind of marks that the different media make and the combination gives you a wider 'vocabulary'.
I had to work out ways of dealing with the fact that he is so intensely black - even his whiskers, He was sitting on a cream chair so I just kept the background simple as it shows him off quite well
Charcoal is a lovely thing to draw with even without the paint underneath. The paint adds colour though so that it isn't purely a black and white image - I'm a colourist painter.
Do you fancy trying charcoal?