It’s already been determined that the Shroud is not a painted image. And the fact that it’s a photographic negative would appear to rule out delliberate forgery, since nobody in the Middle Ages knew anything about photography.
Other than that, great job.
Not a photographic negative. But a sun etching through sun bleaching. You need a pane of glass the whole length of the body and an outline painted to prevent the sun bleaching in some areas and the sun from impacting in other areas. The expensive part is the length of pane glass that is the length of the body.