For someone more interested in the Word, than the artifact of the Shroud, you sure post a lot of completely outdated noise from the skeptics sites that has been long debunked. In fact, most of it was long debunked by previous science at the time the skeptics first wrote it in their magazines and books because they simply chose to ignore the science that had already been done. I post the counter facts to point out that fact.
Your litany of early observations of photographic chemicals, although not under those names, is pointless when there are no photographic chemical residues ever found on the Shroud to hold an image no matter how many may have been discovered by medieval alchemists or artists, who did nothing remotely photographic with them, nor, in fact wrote anything about such use. That’s sort of akin to saying the Shroud could have been an early Polaroid photo in a minute because the basic chemicals used in Polaroid cameras were first found in 1100AD, and someone maybe could have made a giant camera obscura Polaroid back then . . .
I bow to your up to date analysis, with respect for your respect for historicity, but I still don’t need the Shroud in my Christian wheelhouse.