|The difference between those areas within the blue and red rectangles may possibly have theoretical significance as regards the mechanism of imaging (stochastic v deterministic, if you'll pardon the jargon). Why? Read on...|
I won't pretend that I understand the papers by Giovanni Fazio and his colleagues in Sicily, claiming that the Shroud image is the result of 'stochastic' processes, ones that rule out certain image-forming mechanisms, and render others more probable (see link below).
So what are stochastic processes? One could give a textbook answer and say they are the opposite of "deterministic" ones, that they incorporate an element of randomness, as distinct from being totally predetermined. The analogy that is generally given is that of rain falling on a pavement. Gradually a pattern of drops develops, but the location of each drop is not pre-determined, but random.
Here's another attempt to convey the difference between the situations, free from as distinct from incorporating a random element, cribbed from internet image files: chess v snakes and ladders (the latter requiring dice)
So how is that relevant to the Shroud image? Again, I don't pretend to follow the authors' line of reasoning, but gather it's related to what's been called the 'half-tone effect', a topic I was discussing not so long ago. The half-tone effect is a shorthand term for a peculiar feature that is claimed for the Shroud image, namely that regions of differing image intensity do not have linen threads and fibres of differing colour intensity. There are either uncoloured fibres, or fully-coloured ones with no in-betweens. A region that looks dark has a higher proportion of coloured to uncoloured fibres compared to one that looks pale. Think of it if you like as comparable to analogue versus digital stereo. The analogue audio signal can take a whole range of values across a smooth continuum, whereas the digital signal is simply a series of binary digits, either 0 or 1.
So where does Thibault Heimburger MD, Paris-based French physician and member of the Shroud Science Group enter this story? Some might be surprised to find his views being favourably received on this site, given there is so much on which we differ, notably the contact scorch hypothesis (one that TH rejects). But that does not mean he's wrong - or right- on everything, far from it, as my follow-up to a recent comment on his on shroudstory.com will now show.
TH appeared on the recent thread, the latter flagging up the presence of a Fazio et al paper recently published in Mediterranean Archaeology and Archaeometry. He queried the claim (or supposition?) that yellowed fibres were randomly distributed across Shroud image-bearing regions, stating that they could appear together in bundles (see copy/paste below). Were that correct, it would deal a devastating blow to any theory that required the coloured fibres to be randomly distributed (though occasional clumping is not totally ruled out, albeit being of low expected frequency).
I recalled that TH had recently acquired from STERA's Barrie M.Schwortz a collection of Mark Evans photomicrographs of Shroud magnified close-ups, e.g. x64, and have just spent the last few minutes perusing them, and selecting one in particular for enhancement in my MS Office Picture Manager.
Here's one in particular that backs up TH's claim for "bundles".
It seems fairly clear that one has two adjacent threads, one comprising mainly yellow fibres, the other largely uncoloured ones. The chances of that happening via random processes must surely be vanishingly small.
Here's the same picture after adjusting brightness and contrast that makes it easier to see the difference.
Sorry, Dr.Fazio, but I think your focus on supposed "stochastic" processes is simply unwarranted, and have TH to thank for making that point. Apologies to the latter for possibly pre-empting him, had he been intending to publish pictures from the same Evans archive.
But there's a sting in the tail for TH: juxtaposition of coloured v non-coloured threads, such as we see above, is I believe entirely consistent with contact-scorching, e.g. from an apposed heated metal template, and is difficult if not impossible to fit into any other of the proposed models that I'm aware of, especially ones that involve radiation of some sort, or diffusion of gases.
Copy/paste of TH comment.