Well there you go.

I remember seeing an experiment where someone was trying to re-create the shroud, they did it by paintig the cloth in a silver compound and placing it in a darkened room with a small amount of light with the light source behind the cloth and the subject in front, left it for days/

It worked with an almost exact replication, so they thought it was a first atttempt at photography rarther than a shroud that someone would have been wraped in at burial.