For this exercise I started on hot press watercolor paper and created an energetic background using a layer of gesso to start in order to get a nice texture. After the gesso dried I added watercolor paint, charcoal, acrylic paint, water soluble crayon, pencil, and more gesso. Lifting off areas of paint where I felt it was necessary and adding more marks when needed. After working on it for a little bit and getting it to a place where I was happy with how it looked I then added the ink portraits over top. You can use the same reference image (below) or any image you would like.
Here are a lot of great reference images that you could also use.