I started creating silhouettes back in 2000/01 after noticing that I could use old Reservoir Dogs poster I was going to throw out as a template. I started off making these at A1 (I think there might still be one at this size stashed in the attic), using a square of plastic to drag and mix the paints together and building up colours.
Careful cutting with a knife meant I ended up with two contrasting pieces, as can be seen here:
I used the technique for a variety of pieces such as this one:
And here's a couple of commission pieces I did for friends: