I did this in college. it is charcoal and chalk on gray paper. It has been in a portfolio for years and years, slightly folded and the charcoal was never fixed.
It is very much a likeness of my Mom who is Still enjoying life with my Dad and their friends on Long Island!
While living in Bronxville and working in Poughkeepsie at a Fine art bronze sculpture foundry (Tallix), I created a large set of acrylic, ink and prismacolor pencil on color paper works (possibly a total of 30 or so works)
Here is one on a subtle purple paper. It's 13 in. x 20 in.