Today our model was David Abercrombie. We did one long pose for the whole class. In my demonstration I showed you a relatively new paper made by Arches (see link below) which is 100% cotton and made specifically for use as a surface for oil painting. This is unusual because traditionally painting on unprimed paper is a bad idea for many reasons. It also works well for acrylic but there are other papers that are also nice and a lot cheaper that work well with acrylic. I will list some of them below as well.
First I demonstrated drawing with charcoal then adding acrylic medium to essentially turn the charcoal into paint. There is a really nice ghostly quality to the black lines when you work this way. You get a nice combination of line and brush strokes. Then I continued to paint into this drawing with white acrylic paint to bring out some highlights. There are many variations on this you could use - more acrylic colors, semi-transparent and opaque layers etc. You could also use chalk pastel instead of or in addition to charcoal.
Next I talked about "drawing" with paint. By that I am suggesting a different way to think about drawing. Drawing with a brush and paint gives you a wider range of line thickness to the point that I was able to draw the whole torso with a single stroke with a large brush. This allows you to approach the various parts of the body as masses or shapes rather than seeing them as contour lines. This isn't better or worse really - just different. It can help you see relationships between parts of the body more clearly or at least in a different way.
After blocking in the figure as interlocking shapes using a dark value, I used a smaller brush to add general areas of highlight. Once I have these basic proportions and values blocked in I am ready to refine the drawing with more detail.