I am unqualified to argue any point, but in my readings I learned that the coloration on the shroud does not penetrate as deeply as a single fiber. Doesn’t sound like paint. I’ve also heard it claimed that it was painted during the Renaissance, but I don’t believe that at that time people were aware that the nails went through the wrist rather than the palms of the hand. As I say, I’m no expert; feel free to correct me.
I am facinated by the Shroud, but I don't know much about it. In the TV show last night, they had a doctor who said the nails went through the palms, however, not the wrists