When one medium is unable to deliver all the capabilities that you desire in a picture, then combining
different media can add extra possibilities. I like the spontaneity and gradations that watercolour provides as a
background, but I also like the degree of control that hard pastels allow. Using medium roughness paper provides a
surface where paint can sink in yet pastel can float over the top of the paper, providing distinct levels in a picture. A watercolour background can substitute for coloured paper, allowing erasure of any mistakes in the pastel layer, and the pastel has a great capacity to mask errors in the watercolour if it is worked into the paper, yet it can float over the top if applied lightly.