OK, I give up. What on earth is a “tilma?” And why is it impossible to paint images on them?
A tilma was a garment worn by peasants, it’s simply a cloak made from local plant (cactus) material and, under normal circumstances, would deteriorate in a few years. One could paint on them but the tilma in question has no known paints or brush strokes on it. Scientists cannot explain how the image was made.