(Note: this follows on from the previous posting:
Here again is a scorch onto linen from an “overheated template” held “excessively long” against linen to produce a intense scorch – one that folk would probably regard as too intense to stand comparison with the fainter more subtle sepia discoloration of the Shroud image.
Yet even STURP commented in its summary on the resemblance of the Shroud image to that of a scorch. So the modelling continues, now with what I consider an improved procedure with “linen-on-top”, one that may work not just by contact/conduction scorching, but via secondary effects more remote from the immediate site of contact due to superheated steam and perhaps pyrolysis gases. Maybe it’s better described as a conduction/convection model.
Regardless of mechanism, one needs to know how well or otherwise the appearance of both moderately and excessively scorched fibres compares with those of the Shroud. Here, without comment, is a series of x40 pictures of those excessively scorched fibres. Lower magnification pictures would have been better, say x32, but my microscope in USB-cable linkage to the laptop does not permit that. I tried Thibault Heimburger’s suggestion of replacing the USB attachment with a standard (x5 objective) lens to give an overall magnification of x20, and taking photographs through the eyepiece, but have so far seen little but bright circles of light!
Sorry about the stray curly blue strand in all the pictures. It’s some debris in the USB eyepiece which is a sealed unit.
So there we are are folks -the worst case scenario. The threads and fibres are unlikely to be much darker than the ones you see above, at least not at temperatures (220 to 315 degrees C we are told) that produces scorches vis pyrolysis of hemicelluloses, as distinct from the cellulose pyrolysis and progressive carbonisation that would occur at higher temperatures (315-400).