Tried something different today..
did a digital tonal painting using a large paintbrush for as long as possible,
and then go in with a finer brysh to add detail.
1) large oil rough bristol brush for sketch

2) using the same brush I started to place lighter and darker tones

3)I then started to put in midtones and blend some areas

4) Blend in some more and where I started to loose shape I went in with a hard brush to create a solid edge.

5) With a much smaller brush (oil round bristol) I started to paint the face,
and blend some more areas. I then adjusted the levels of the image to get more of a contrast...

This is obviously far from finished, but the aim of this exercise wasn't to get a pretty picture but to try out different things...