Searching for contrast.

Well tonight I decided to just do some digital drawing/painting...Alas I always seem to end up with image that has low contrast. Usually my work method is something like this:

Poor use of background + Low contrast = Visually boring image.

So, just for fun I copied and layered stuff together, inverted and many other things to see what other contrast combinations I could get. I see that Guillermo is doing just straight gray scale paintings and I'm thinking I might have to do that. I need more contrast in my images to help sell the poses of the characters. Granted I have seen artists make some amazing images with very little contrast to them. I guess I'm just looking for it in my own stuff at the moment. Chris gave me a couple good examples of still life's in mono or close to mono chromatic paintings at work a few days ago. Anyways enough rambling here is what I have thus far.