A combination of leaves, copper leaf and copper wire. I wrap the wire around the entire canvas to keep the tension, and after coating it with medium, I cut it at the edges where I paint over it.
I am making the material from scratch using layers of acrylic medium, a texture layer, and a layer of metal leaf. The process takes 10 layers, and one month including curing the acrylic. The material can be rolled, folded, and cut with sizzors.