Stop press: this posting of mine, probably the last for a while, possibly the VERY LAST, unless or until the Shroudosphere sees a
major significant new development, has been described on The Other Site as a “better posting, perhaps his best “.
I now feel the kind of elation that J.R.R. Tolkien might have felt on seeing “The Adventures of Tom Bombadil” hailed as one of his better books, perhaps his best. 😉
Reminder: the faint yellow/brown image of the Man on the Shroud is said to be incredibly superficial – confined to the outermost 2oonm of the fibres. That’s just 1/50,000th of a millimetre.
Can the Shroud image really be so superficial as we are led to believe – whether on the PCW or Rogers’ proposed encrustation with acquired impurities – one that is reportedly too thin to be resolved under the light microscope? Read on.
Even if it were up to 3 times as thick, as some suggest, based on these figures being guesstimates, that’s still amazingly thin. How can an image that has captivated people down the centuries (whichever one you take as your starting point) be so superficial? Or is it really as superficial as we have been led to believe, based on some perfunctory tests with sticky tape and forceps (thinking of the STURP claim that one can strip off an image fibre with sticky tape, and then pull away a clean fibre leaving the image layer behind as a coloured “ghost”, too thin, too superficial to be properly resolved under a light microscope, and thus presumed to be a few hundred nanometres thick at most)?
But as pointed out a short while ago, that ultra-thinness hardly squares with the reports that image fibres on the Shroud can be stripped off more readily than non- image fibres. What’s more, image areas show broken fibres. Put those two observations together, and it seems clear that image fibres are weaker and/or more brittle than non-image fibres. How can that be, if the image is confined to the most superficial (outside) part of a fibre, which some see as representing the primary cell wall (PCW), a mere 50th or thereabouts of the diameter of a entire fibre, which is typically 10,000nm in thickness? What price then the claim by STURP team leader Raymond N. Rogers (RIP) that the image was imprinted not on the fibre per se, but on an impurity coating, variously proposed as one or other 1st century AD adjunct (e,g, starch, soapwort) said to have been used routinely to facilitate weaving or bleaching.
For the entire fibre to be brittle, the internal structure of the fibre would have to have been weakened by the image-imprinting mechanism (although we are told it is uncoloured) . Is that possible? At first sight no, since the interior of the fibre, except for a narrow central lumen (a “hole”or “tunnel” in which resided the initial living stuff of the cell) consists of tough cellulose fibrils which run the entire length of the highly elongated fibre cells. Those fibrils are said to resist being broken across their width, at least in untreated flax fibres, unlike the primary cell wall, which not surprisingly is easily fractured across its short width.
So here’s a photograph of a linen fibre that Hugh Farey sent me a couple of days ago, highly magnified (x1000). (See previous posting which included it).
What’s special about it? It shows those cellulose fibrils of the inner secondary cell wall. There’s a hint of their helical configuration (with the eye of faith, well, slight curvature). Notice anything? They are fractured! Oh, but I have overlooked to mention something important – the linen fibre was taken from a scorched thread.
See postscript for the reason why I have scored out the above caption and text. (As I have said on a number of occasions, this blog is by way of a work in progress, an honest account of one man’s learning curve). I’ll supply a new caption in due course, or maybe delete the picture altogether.
Raymond N. Rogers argued against the Shroud image being a heat scorch, maintaining that anything hot enough to produce a heat scorch would affect the internal cellulose of the fibre, but there was no sign of that, he said, inasmuch as the cellulose of the Shroud linen showed normal birefringence (double refraction of polarised light) under the microscope, suggestive of undisturbed crystallinity (debatable, but let’s not go into that right now).
But let’s not forget one thing. The secondary cell wall is not 100% cellulose. As I pointed out in the last posting but one, the SCW is reckoned to contain non-cellulosic polysaccharides (NCPs) as well (some 15% of total polysaccharides) which are hemicelluloses, with a sizeable galactan content. Hemicellulose may sound similar to cellulose but is entirely different, having much less crystallinity, and lacking therefore the extraordinary physical strength and chemical resistance of pure cellulose. Being non-crystalline, and accompanied by pentose sugars, the hemicelluloses of the SCW (secondary cell wall) , AS WELL AS THE PCW , may well be susceptible to scorching by conducted heat, weakening the fibrils, making them more prone to fracture across their width – not just separate longitudinally. Maybe that scorching would not be highly visible, and perhaps easy to overlook, if it were to be interspersed with white cellulose fibrils. Rough-and-ready microscopy may not tell the whole story, especially on account of refraction artefacts etc. Oh, and let’s not forget the nodes either (aka dislocations) of which there are reckoned to be hundreds per fibre cell. They too have been described as weak points in the flax and linen fibre.
Take away message? At the risk of boring the pants off everyone with the same old refrain, I for one shan’t be abandoning the scorch hypothesis any time soon. It’s got too much going for it. Where there still exist unexplained discrepancies between model scorches and the TS image, e.g. colour distribution, fluorescence etc, they may well be due either to differences in the scorching methodology (there being numerous ways of ‘ringing the changes’) or of age-related effects and/or ‘traumas’ experienced by the Shroud in its history (1532 fire etc).
This will be my last posting for a while, possibly for some weeks, since I now have other
matters to attend to interests to pursue. I shall continue to complete and tidy up some previous postings, notably Rogers’ FAQs that generated an unexpected level of interest (and, I’m delighted to say, surprisingly little by way of negative comment). Comments will still be welcome, which I hope to respond to within 24 hours or so. Au revoir….
Postscript: there is some ongoing discussion about that graphic of Hugh’s above – and what it represents: a linen fibre with internal fibrils, or a ‘technical fibre’, which is an association of fibres. It was I who suggested to Hugh the first of those two interpretations, given the very high magnification (x1000). Thibault Heimburger queried that magnification, but Hugh was adamant it was taken at x1000. Thibault for his part was equally adamant that the internal structures were fibres, not fibrils. I make no claim to be an expert in this area, having only recently become acquainted with it. But I do know how to use MS Paint, so have put Hugh’s x1000 picture alongside a x1000 SEM from another Frenchman by the name of C.Baley, judging by his institute (Lorient in Britanny) which clearly is a ”technical fibre’ made of fibres, each with a central lumen.
There is some size discrepancy re the diameter of the fibres (NOT fibrils), roughly by a factor of 3, probably due to it being a non like-for-like comparison (linen v flax, light v SEM microscopy, scorched v unscorched). Nevertheless, despite the size discrepancy, the conclusion seems inescapable. I believe that on this occasion Thibault’s interpretation is the correct one, and my initial impression, put to Hugh in a comment, was incorrect. The misidentification arose because Hugh’s photograph was, it would appear, not a complete linen thread, but a so-called ‘technical fibre’ comprising a much smaller collection of fibres, and it’s been suggested there was enough un-retted pectin still around to give a sheath-like appearance that seemed out of place for a thread, but could be (mis)interpreted as the PCW of a single isolated fibre.
Enough of excuses: Thibault got it right on this occasion. But that’s no reason for the entire Shroudosphere to run away with the idea that Thibault is right about everything all the time. For example. I don’t think he was right about his rejection of the scorching hypothesis on the grounds that a heated bas-relief template must always produce a scorched-on image with “excessive contrast”, not when his unsubtle choice of template virtually guaranteed that result! If folk are wondering what on earth I am talking about, it’s because another site that shall remain nameless chose to ignore completely my 3 part-riposte to Thibault’s assault on the scorch hypothesis, while continuing to this day to give his pdf prominence at the top right hand corner of its Home Page.
BRAIN TEASER added Thursday am
Can anyone explain why some fibres in Mark Evans’ close-up of Shroud body image ( indicated by the red arrows below) run horizontally when there’s the expected twist in the adjacent (and presumably underlying) thread and elsewhere?
Note too how dark that band of horizontal fibres is relative to surrounding threads. Observe too the isolated broken fibres here and there that appear to be much darker than the general honey-colour of the image fibres. Some look dark brown. It is not inconceivable that centuries ago the the image fibres looked much browner and easier to see, and that there has been a process of attrition, with darker ones gradually snapping in one or more places and falling off (or rubbed off) to leave the relatively less coloured fibres that give the current Shroud image its homogeneous appearance. What price then the “half tone” idea – that differences in Shroud image intensity are not due to differences in colour between one fibre and another but, mysteriously, to differences in the number of (uniformly) coloured fibres per unit area? As orthodoxy goes, that’s a fascinating mantra to intone – that the Shroud image is not only vanishingly thin, but, as if that alone were not sufficiently near-miraculous, it has a half-tone effect that anticipates modern newspaper printing technology. There again, one may simply be seeing the results of centuries of wear and tear – or rather wear and multiple fibre fracture. Wear and tear sounds more snappy (pun possibly intended).
Oh, and here’s a handy diagram, discovered by searching “flax fibril” in image files. It shows what might be described as four levels of organization, starting with macro-scale (flax stem) and ending with nano-scale – multi-layered cellulose(70%), hemicellulose (15%) and pectins (2%). The progression goes anti-clockwise note.
What it does not show is how there can be a progression of stages in retting, depending on how far the individual elementary fibres are separated by loss of the pectin cement. One presumes that a ‘technical fibre’ is an intermediate stage, with two or more associated fibres, but fewer than the full complement that exists in the flax stem bundle. But as I say, I am no expert in these matters. Does anyone know if the quality of linen is affected by the presence of ‘technical fibres’, i.e. the greater the proportion of associated as distinct from entirely separate (uncemented) fibres, the lower the quality? What about the Shroud linen? Free fibres, or lots of ‘price-competitive’ technical fibre?
Eureka! Here’s another handy graphic I’ve just discovered that plugs the gap above, showing the intermediate role of that so-called ‘technical fibre’. Don’t ask me why it’s called that. Is it because it’s the right size to be used in modern composites, with advantages over fibre glass in particular applications – as distinct from being a standard feature of linen, whether of 1st, 13th or 21st century origin?_________________________________________________________________