Re:First photo? Wild Turin Shroud theories... (Score 1)

Wrong - it is certainly NOT a painting. The simplest reason is that the pigment on the extremely fine linen showed NO seepage to the underside of the thin fibers, impossible if a liquid is applied. There are many other points of proof.

It is almost certainly a camera obscura image - see this page, halfway down, for a description. It may or may not have been Leonardo (the painted version showed up earlier, but is posited in this case to have been redone under commission by Leonardo), but if not, it was done by another extremely capable artist using available painter's chemicals to create the light-sensitive substrate. To the point that the artist would have used his own body, probably there are better ways to spend one's time than standing motionless covered in white paint in the hot Italian sun for hours (a cadaver would do just as well).

Need some strong evidence? A recreated version of the shroud as a photograph that is extremely compelling can be seen halfway down this page. It is actually of much higher resolution than the shroud, but was made using the same camera obscura process.