Overall conclusions so far:
There is no evidence so far that real hair has been imaged, given there is nothing strand-like that lies at a different angle from the zig-zag ribs of the herringbone weave.
Is that really so surprising? If “real” hair of a subject had been dry at the moment of imaging, then it is difficult to conceive of any mechanism that would leave an image of its ‘strandedness’. Had the hair been wet and then applied to a dye-impregnated fabric, then in that situation one might perhaps have seen strands. Alternatively the hair itself could be dye-impregnated to leave an imprint of strands. But either of those mechanisms requires a a liquid-suspended pigment of some kind for imprinting – but we are told there is no evidence for any pigment in the weave of the fabric, and there is no evidence either in the images above, shown by the absence of appreciable image in the furrows between the ribs, far less a clogging of the furrows.
What about heat – or some mechanism involving high energy radiation? Might that have been responsible? In the absence of added pigment, that would require require a chemical modification of the linen fibres to leave an imprint. But if there were sufficient energy to cause the kind of reactions that leave a scorch-like mark on linen, then the energy would probably have degraded (“singed” in common parlance) hair too – which is keratin – a protein.
There is another possibility that has to be addressed, namely that what was imaged was not real hair, but a representation of “hair” that was not of human but inanimate origin, and one that was sufficiently robust in terms of chemistry to survive the kind of physical and chemical changes that left an imprint on linen.
What might that representation of hair have been? I believe that a lot of aluminium was detected on the Shroud (and will attempt to locate some quantitative data). Aluminium is a constituent of clay, and clay is used to make pottery, with or without firing at high temperature (an initial “biscuiting” at low temperature being sufficient to produce a reasonably strong piece of pottery). My working hypothesis is that the Shroud was made from a template of clay that had been moulded and then marked (while still plastic) to give the required detail – scourge marks etc – and on which beads of clay could have been used to simulate blood stains, with or without subsequent touching up of the template or Shroud with some real blood, or suitable coloured pigment that might be mistaken for blood, especially aged blood. Those beads, once set, would have been slight protuberances on the surface of the “skin” that would then have left a stronger imprint in whichever imaging process was used through making better contact between template and fabric. In this model the face would have been little more than a rather shallow bas relief, that was then framed, so to speak, with a border to represent hair, while making no effort to give that “hair” a realistic stranded appearance.
Everything I have seen so far is interpretable in terms of a mechanical imprinting process between template and linen. Whether the process was purely thermal (“scorching”), purely chemical , or a combination of the two (similar, say to invisible writing with lemon juice – with subsequent heating to develop a sepia image) is something I shall consider and discuss in future posts. In the meantime, I shall complete my inspection of the Shroud with the magnificent Shroud Scope,