Drawing With Milk

I cut up some newsprint into small squares, I drew on these pieces of paper using milk, the drawing at first was only visible for less than a minute as it soaked into the paper and began to dry fast so a lot of the time I lost track of marks I had made and ended up overlapping certain parts of the drawings. To make these drawings visible again I held the drawing over my fire at home, the heat caused the milk to change colour and become visible. The longer it was held over the heat the darker the milk drawing got.