My new sandpit theory for how the Turin Shroud was produced - as a medieval hoax

 The basic principle - thermal imprinting  from a 3D object

(ed: things have moved on a bit since writing this post. For a more up-to-date account of my theory, see this later post, link  and the one preceding it link)

ed: a lot of the step-by-step photographs have mysteriously disappeared from this post. I will endeavour to restore them ASAP.
The technique is essentially one of 'branding' (yup, as onto the hide of cattle) but the 'branding iron' was more probably a bronze statue - which did not need to be red hot to create a superficial scorch on linen.

This is intended as the briefest of summaries. I propose using my own comments section to flesh out the details, but only in response to queries. In the absence of comments my time is probably better spent in  further experimentation  (continuing the work I have described in previous posts on thermo-imprinting or thermo-stencilling). 


Essence of the new model:

1. It uses a statue or bas relief of a crucified Christ - the kind of icon that would have adorned (if that is the correct term) many a medieval church or cathedral.

2. A shallow sandpit (US: sandbox)  is made with fine dry (ed. or maybe moist?) sand and levelled off with a rake.

3. The sheet of linen is stretched over the top of the sand and smoothed out. The linen may have been impregnated to make it more receptive to acquiring a heat-imprinted image (think "invisible writing" that uses dried-on  lemon juice or similar).

4. The statue is evenly heated in a kiln or oven until a test shows it to be hot enough to make a yellow or brown impression, i.e. 'scorch mark',  on a side-sample of the linen.

(Whether one calls it a scorch or not is a matter of semantics that can be discussed later. Certainly it does not have to be hot enough to degrade or scorch bulk cellulose per se, except perhaps for a highly superficial imprint).

5. The heated statue is then placed face-down horizontally onto the linen, and pressed down lightly.

 Except for awkward bits like the feet (see later) the statue is probably pressed no more than a cm or two into the sand, just sufficient to imprint as a light scorch the most prominent frontal features of the statue onto the linen, with little of the side features that might otherwise later give distortion when the cloth is removed and flattened.

The image would of course be a "negative", but that has nothing to do with photography, primitive of otherwise. The technology here is better described as thermal-imprinting by direct contact, relying mainly on heat conduction rather than radiant energy..

6.  When a satisfactory image has formed of the ventral (frontal) side, the second unused half of the sheet is positioned over the newly raked sandpit, and the process repeated for the dorsal (rear) side of the statue.

7. What about the blood stains - getting them correctly positioned etc? That can be arranged by a slight modification of the procedure.


It requires a "dry run", or more correctly a "cold run". Firstly, the cold, unheated statue is pressed onto the cloth  so as to penetrate the sand a little, leaving an indentation in both the sand and the linen. The statue is then carefully removed, and blood is then applied to the appropriate parts of the anatomy, as judged from the indentation.  It may be left to clot and dry first. The statue is then taken away and heated, and then deposited carefully back into its original indentation to ensure consistent alignment, then pressed down a little more into the sand in order to get a good impression.

8. Created in this way, I believe the image would meet some subtle criteria that so far have not been fully achieved, e.g. in Jackson's work with his bas-relief models (see earlier post).

I believe a balance can be struck that can achieve a good compromise between a shallow bas-relief and a fully 3D statue.The compromise gives enough relief to account for 20th century "3D-encoded information" - which if the truth be told is really just an (over-hyped) analogue- to-digitized impression of 3D, ie differential scorching- to-computer-aided graduated relief.  The dynamics of the pushing process, ie. - the gentle pressure on the statue, impressing it into the fabric and into the receptive cushioning sand to achieve progressively greater contact between cloth and hot metal is what helps to achieve a softer-focus more natural effect.

9. Because the statue is pressed downwards into the sand, i.e. at right angles, that would account for the so-called "directionality" of the image-forming process.

Attempting to explain the latter with radiation and projected images has been problematical, in the absence of lenses, concave mirrors, collimating systems etc., none of which are credibly medieval or indeed achievable today

10. This procedure might also explain some of the curious - or at any rate unexpected - features of the Shroud, e.g. the somewhat elongated fingers.

  Those fingers  (to say nothing of those "too good to be true" blood trails on forearms and that celebrated  "mechanically-correct" nail wound through "wrist").

That could be the result of a "sliding effect" of those hot fingers (one of the the first parts of the statue to hit the fabric) during the first few moments of pressing into the sand. It might also explain why the soles of the feet are so prominent on the dorsal image, despite their being out-of-horizontal plane, since the sand-moulding influence forcing fabric against metal would be largely indifferent to plane.

  

Why are the soles of the feet (even if blood-stained) so prominent in the left hand image (dorsal view), with subject's back to linen? What had been holding the linen so close and tightly apposed to them at the instant of image-imprinting? A bed of supportive sand, banked up maybe?

 To get a better idea of how soles come to be imprinted, and how they look on the flattened sheet, imagine yourself lying down on a sheet with muddy boots, first with heel-only contact, then imagine you ask someone to raise and then press the end of the sheet against the muddy soles to leave an imprint. Then imagine how the imprint will look when you get up and view the flattened-out sheet from above.


Comments - premoderated - are invited, but ad hom attacks will not be tolerated (or published)   If posting as "anonymous" please append an initial or two.

The Turin Shroud - a bit of bas-relief

Multiple thermo-imprinted images from a single bas-relief template obtained as the trinket cooled down

Yes. I've given up on thermo-stencilling for a bit (see previous posts) and am now experimenting with bas-relief. So far I've merely repeated what John P Jackson of the STURP team and others have done - which was to produce a scorch mark on untreated linen with a heated bas-relief object (in this case a trinket I picked up while in Ghana). Yup, I know that the Turin Shroud is not a scorch mark according to the admirable Raymond N Rogers (RIP). But Rogers was not infallible - indeed I shall shortly be putting some of his experiments and conclusions under a fellow (bio)chemist's, er, microscope, and in any case Rogers only said it was not a scorch onto bulk fibres in linen. But that did not preclude the possibility that it was a thermal - or maybe chemical imprint onto a superficial layer of something else that was more thermo-sensitive than cellulose, as Rogers himself proposed. eg. starch, or simple hexose or pentose sugars.

However, experimental work will have to be put on the back burner for a while (literally).   I am presently composing a critical overview of another paper that has been pushed under my blogging nose, namely that of Fanti et al on the use of computers to re-image the "true" (ho ho) ventral and dorsal  ("front and rear") anthropomorphic dimensions of the image on the Shroud.

Forget those miraculous flashes of ultraviolet light - was the Turin Shroud produced simply with medieval technology - heat conduction and scorching?

Could the Turin Shroud have been made in medieval times as a hoax or fake, simply by scorching an image onto linen, say from a 3D representation of the crucified Christ? 

Could the latter have been a ‘bas relief’, i.e. a raised image on a background, comparable to a medallion say (albeit much larger) or even an intact statue, fully in the round, so to speak?  Was the bas relief or statue heated and then draped with cloth to produce a scorch mark corresponding with the relief (thermal imprinting).  These were questions that John P Jackson of the STURP team addressed back in the 1980s.   

 John P Jackson

Here from Stephen Jones’s splendid site is an account of Jackson’s work, shorn of references to keep it uncluttered, which I have interrupted and annotated to insert my own sceptical views (in blue).

John P. Jackson:
"Heated Bas-Relief/Scorch Theory Another possible image-forming mechanism similar to that proposed by Nickell involves pressing a stretched cloth over a heated bas-relief. Such an idea was first proposed in 1961 and tested, with limited success, by placing a white handkerchief on top of a heated small medallion that bore a carving of a horse. This theory is more intriguing than most because the Shroud image does appear to have many of the physical and chemical properties of a light scorch.  STURP scientists Jackson, Jumper, and Ercoline tried to duplicate the image on the Shroud by testing the scorch hypothesis more fully. To accomplish this, they heated a full-size bas-relief model of a face and stretched over it a linen cloth of a thickness similar to the Shroud.  The ... resulting image lacks the high resolution and sharp focus found on the Shroud.

 Later, John Jackson (kneeling) used real human models, at least those with a passing resemblance to YKW...

High resolution? Sharp focus?  I doubt whether those viewing the Shroud up to the end of the 19^th century would have described the image in those terms, indeed modern day viewers too. It was not until  the first photographs were produced that the friendlier “positive” image became available. 

The very first negative-to-positive transformation of the Shroud image (1898)

The subsequent 110 years or so have seen progressive advancements in imaging technology, bringing ever greater resolution, clarity, (claimed) realism etc. But how much is electronic and digital tweaking to produce the best picture, regardless of the information content of the faint sepia image with which scores of generations had to be content.

“While the bas-relief method seemingly yields a respectable three-dimensional image, problems are evident in the accompanying VP-8 relief of this image.

 VP-8 image-analyser

Hollow spots below the eyes, next to the bridge of the nose, below the lips, in the beard, and on the forehead are all noticeable ... . Further, a slight plateau is visible on the high spots of the VP-8 relief, similar to those produced in VP-8 analysis of results from experiments with direct-contact methods.

A respectable three-dimensional image?  I raise my hat to Jackson – those are words you will rarely see in the current Shroud literature that holds the image is genuine 1^st century AD, indeed the actual burial shroud of Christ.. Most are dismissive, indeed comtemptuous of any modelling with bas-relief etc, claiming that those techniques fail to produce ALL the characteristics of the Shroud image. And what tops the list time and time again? Yes -  you guessed it – those  claimed “3D-encoded characteristics” 

 3D image of Turin Shroud from VP-8 image analyser

Yet here we see Jackson conceding that an inanimate bas-relief produced a 3D image on cloth by simple heat conduction (”scorching”).

So the image of that bas-relief was deficient in some respects (hollow spots below the eyes etc)  Yet for centuries,  sorry to repeat myself, the eyes on the Shroud were little more than white hollows, but now, with the technology at our disposal,  it is the photographic positive (naturally) is now being held up as the gold standard!  “A slight plateau on the high spots” ? Did Jackson not consider modifying the bas-relief template, which was maybe too flat, or ringing the changes any other the other numerous variables that might have been tweaked to get a better image?  Science is about establishing principles, not replicating every tiny detail of the arts and crafts, especially as the materials used were unknown. Science needs cues if it is to make a contribution. Science cannot be expected to travel back in time to discover precisely what materials and techniques were being employed. Science  is a method, an approach, not a magic wand. Science has its limitations...

"Even though the heated bas-relief produced better three-dimensional information than other methods, Jackson and colleagues concluded that this process could not encode many of the necessary Shroud image characteristics. For example, regardless of the temperature of the bas-relief, thermal discoloration appeared on the back side of the test cloth within several seconds after being placed on the hot bas-relief. Thus, the superficiality characteristic is violated because the image could not be encoded only on the topmost fibrils of the linen."

A thermal discoloration on the back of the cloth? Would that by any chance be the “faint reverse side image” that we are told is one of the unique characteristics of the Shroud that no one has replicated, or can ever hope to replicate?

But the main characteristics we are told is the highly superficial image on the front side, so superficial as to defy modern science. Yet Raymond N Rogers provided a simple explanation for the superficiality, based on his crucial observation that the image could be stripped off with adhesive tape. The image is not on the cellulose fibrils of the actual cloth he said, or,  if it is, only on the most exposed ones. The image is formed on a layer of adhering carbohydrate that is not cellulose, but something chemically more reactive, more prone to dehydration and scorching. The latter is a matter of  speculation  –  it could be starch, simple carbohydrates, saponin  etc, all of which have been proposed, either acquired adventitiously, e.g.in linen weaving and manufacture, or purposely as a known thermo-sensitive substance that would brown on exposure to heat (think invisible ink, think gravy browning etc.). Either way, there is a COMPLETE explanation for a faint image forming on both surfaces, but not the intermediate (bulk) cellulose fibres. Cellulose, as we know, is highly resistant to degradation by heat, oxygen etc on account of its highly ordered crystalline nature -  a function of the multiple hydrogen bonding interactions between beta-linked glucose molecules. 

Here is a scorch image I produced on cotton using simply powdered charcoal as a thermo-sensitizer and heat from a 60W lamp ( photographed after washing out the charcoal). Think how much easier it would be to scorch a surface layer of more reactive carbohydrates (fruit sugars such as glucose, sucrose etc)

Other carbohydrates, e.g. starch with its alpha-linked chains in amylose and amylopectin are less stable, and simple mono and disaccharides more so, especially the reducing sugars like glucose. Simple sucrose, which easily splits to glucose and fructose, can be the agents for easy caramelisation (browning) when exposed to heat.

“The researchers tried to circumvent this problem by wetting the cloth, thereby extending the scorch time. When this technique was tried, new problems appeared. The image's contrast was reduced, causing more severe distortions in the three-dimensional analysis and resembling images obtained from direct-contact techniques ... In addition, because the cloth was essentially flat when the image was encoded, tests of this image-forming method failed to generate an image that contains the subtle lateral distortions that are consistent with the cloth-drape effects found on the Shroud."

Again,  these difficulties are less to do with science, and more to do with technology, indeed arts and crafts, difficulties that can or could have been be overcome by trial and error. Mimicking “subtle lateral distortions” may require nothing more than a stretching and/or ironing technique, instead of simply draping cloth over a hot template.  

These are the Italian scientists who think you need high energy ultraviolet light to scorch an image onto linen (at a distance, focusing system  unspecified). 

  and this is their equipment for modelling a 1st century miracle (leaving a superficial scorch mark on cellulose)

Returning to Planet Earth: what about Jackson's Hot Statue method?  Critique to follow...

Effect of twiddling the gain control

This I believe to be the way to go (but replace the person with a bas relief template or statue): and spend time on ringing the changes with those critical experimental variables, too numerous to mention:

..

The Shroud of Turin - think of it, if you will, as a medieval EuroDisney, designed to attract thrill-seeking tourists, oops, sorry, devout religious pilgrims...

Here are (sorry) 38 points to consider regarding the Shroud of Turin. I may add some more later. I will discuss details and/or objections on this blog (comments premoderated) and nowhere else.

Comments that accuse me of being an internet  troll or similar will not be published. Kindly read my credo, in place since I began "Science Buzz". This blog is primarily about my scepticism re media-hyped gee-whizz science, especially 'pseudo-science', as previous postings will demonstrate, NOT religion...

1.The Shroud was produced by heat-imprinting onto linen, the latter having been coated or impregnated accidentally or intentionally, probably the latter, to make it weakly thermo-sensitive. 

2. The imprinting was done from a template that could withstand heating. It was neither realistic fully-rounded 3D, eg not a statue, nor even a mummified cadaver, except possibly the hands  – as I suggested previously - nor was it 2D (obviously).

3. As many before me has suggested, it  was probably a shallow bas-relief that was created on soft stone or perhaps a soft metal by chiselling, sanding, engraving, gouging etc.

 A  shallow-cut modernistic bas-relief of the crucified Christ 

 Here is a more deeply recessed bas relief

Such objections as I have seen that attempt to dismiss bas-relief do not stand up to close scrutiny. 

4. The relief depth may have been at most a few cm, possibly as little as a cm or less.

5. Dorsal and ventral imprints may have been obtained from two different templates.  Some claim dorsal and ventral images are not consistent. A quick play around with my laptop would suggest as much.

Size disparity - dorsal and ventral images on two halves of Shroud

6. Separate templates may also have been used for the head and rest of the body. Some say the head is too small.

7.The hands and fingers especially were poorly executed, being far too long, and too bony. If really indicating an “X-ray” like quality to the shroud, then why is there not more of a skull-like quality to the head, say, or to the ribs, pelvis, feet etc?

8. Given the skeletal appearance of the hands, with the metacarpals easily mistaken for finger bones, it would be unwise to attach too much significance to a single blood stain indicating the site of a nail puncture being allegedly through or out of the wrist. 

9.  Flogging. marks were carved/gouged onto the template. The pattern looks too regular and systematic . Given the comprehensive nature of the flog markings, flaying might be a better description. It seems improbable that an individual would have survived long with that degree of trauma and rupture of skin capillaries. Fluid loss, dehydration, shock and probably death would have rapidly ensued.

10.The impregnation of the linen was inspired by the phenomenon of “invisible writing”.

Lemon juice and heat from a 100W light bulb

In its simplest form the latter requires writing on paper with lemon juice, allowing to dry and then heating. A sepia brown image is formed.

11.Probably more involved technology was used for the Shroud, e.g. by impregnating linen with one of more components like starch, simple reducing sugars  such as fruit sugars, proteins etc, that are more heat-sensitive than cellulose, but which also have the properties of turning brown when exposed to heat. 

12.There are indeed references to starch on Shroud fibres, and of the colour being confined to a superficial layer:    

13.The template would have been heated, and when at a suitable temperature, probably equivalent to a modern-day electric iron on its highest setting, the linen would have been draped on top, maybe pressed lightly, e.g. with a roller, and removed at the first sign of an image appearing on the top side (i.e. the one that is the reverse on the Shroud).

14.Some say that pressing a cloth over a real person to produce an imprint would leave a distorted image when the cloth has been removed. That opinion was  comprehensively  dismissed in the case of a cloth lightly draped over a person to give partial conformity with natural body contours. See Mario Latendresse (pdf)

15.If the model was a bas-relief then the cloth could have been pressed against the hot template more tightly without fear of noticeable distortion.

16. There is some evidence that it may have been pressed with a board or batten placed lengthwise.

Darker band in central rectangular area, allegedly due to weave

See sharp demarcation between light and dark. Some attempt to explain this away by claiming that it is batch variation in the yarn used for weaving. But the demarcation line is not perfectly straight on the right side (see cheek bone) which is inconsistent with the latter theory. However, there could have been pressure applied briefly at the margins too, to produce a softer image, less like printing, more like a painting with a gradation of tonal contrast.

17. Produced in this way, by thermal imprinting, the image would have been a negative, with most prominent features, i.e. proud of the surface in the bas relief template making greatest contact with the linen. 

18. Thus there is no need to invoke early “photography”, for which the technology did not exist, at least not one that was capable of producing a final “positive“ image which did not happen until 1898.

 Negative v positive

That “negative” image seems to have been the starting point for much of the supernatural hype, especially when the alleged “encoded 3D” claim (see later) was added later.

19.The image is formed only in the superficial thermo-sensitive coating, not on the underlying cellulose itself – except perhaps for the most superficial fibrils. That explains why the Shroud of Turin image can be stripped away with adhesive tape, as demonstrated in the generally impressive studies of Raymond N. Rogers.

20. Further evidence of the superficiality – and easy detachability  - comes from looking at midline of Shroud, which shows a white stripe with no image. The Shroud has clearly been folded along that axis, as evident from symmetry of the 1532 burn marks.

See my earlier post, showing how this  reconstruction was produced by folding and cutting

Folding has probably caused the overlying film with image to strip off.   http://www.theblaze.com/wp-content/uploads/2011/12/jesus-christ-shroud.png     see white vertical lines. 

21.The method of contact printing explains why the Shroud image has no features that resemble those of a painted image, i.e. no adhering artist’s pigments of the era, no brush marks, no directionality as regards alternation of light and shade.

22. The observation that brown fibres and white fibres are seen side by side under microscope is suggestive of highly localised heating by contact and conduction, as distinct from high energy radiation.

The highly localised "scorching" is highly suggestive of  imprinting by close contact (heat conduction rather than radiation)

(There is another lower-magnification image that makes the same point better, which I have mislaid).

23 .A second factor may operate to produce selective fibre scorching. As soon as a fibre turns brown due to contact heating, it will then tend to absorb appreciably more energy in the form of infrared radiation from a hot template as well. There is then a positive feedback effect.

24.The half-tone effect, i.e. intensity of colour due to number of coloured fibres rather than density of colour, might suggest that the limiting factor in the pigmenting was the availability of thermo-sensitizer. If the latter were limiting, there would tend to produce an all-or-nothing half-tone effect.

25.Whether considered as a fake or the genuine article, advocates from both sides are agreed that the image is in the superficial coating and that the latter is a carbohydrate that is more reactive chemically than cellulose. There is the saponin theory, the latter being used in early linen production and which contains pentose sugars. Alternatively, reactive sugars could have been added immediately prior to scorching, even something as common as sucrose which splits easily into the monosaccharide sugars glucose and fructose - both of which are easily dehydrated by heat and then prone to caramelisation (browning reactions).

26. Is there any evidence of detail in the parts of bas relief that are furthest from a cloth laid over? If yes, it speaks of photographic imaging, e.g.  with a lens or concave mirror.  If not, it suggests thermal contact printing with no sharp image focusing, indeed no depth of field at all, sharp or otherwise. Indeed there does not. Look at the sharply demarcated boundary between dark and light on both sides of the face. There is no suggestion of ears for example, lurking in that deep recess.

 No obvious ears 

An absence of any detail in the lighter portions suggests contact printing rather than image-forming at a distance. 

27.Others have commented on how the hair looks straight and lank as one would expect from a vertical subject. The template for the head may have been modelled on conventional images of the crucified Christ while still vertically on the cross. 

28.Blood may have been applied to the template when cold, then apposed to cloth before heating. Less probably, blood may have been applied to hot template immediately before draping the linen but that would have risked having some of the blood drying and chemically decomposing immediately. There would be no image under the blood marks, the latter having protected the thermo-sensitive coating from heat. Indeed that observation alone would tend to rule out high energy radiation (uv, soft x-ray etc) since the latter tends to be highly penetrating and would have reached the linen through the blood.

29 .It is not clear why blood would transfer so readily to a burial shroud hours, possibly days after being shed, especially from a crown of thorns (which the Gospel writers say was placed in position before crucifixion). It is a characteristic of blood that it coagulates to a solid, horny clot on standing, and ceases to be a liquid, except for the exuded straw coloured serum fraction. The red blood cells that contain the red pigment haemoglobin become entrapped within a network of fibrin fibrils, forming an essentially solid clot.

30. So-called 3D-encoded information is an artefact of the computerised imaging – which explains why the 1532 burn marks appear as a hologram-like 3D as well as the image itself.

Note 3D appearance of 1532 burn marks (at shoulder level) as well as the figure

It is redundant to ascribe “encoded” information to the image if the same 3D-transformation can be achieved on burns acquired in 1532.

31. With a permanent heat-resistant template it would have been possible to experiment with the same template and more than one sheet of linen to achieve an optimal end-result.

32. There can be little or no bilirubin on the cloth, even after days and weeks, never mind centuries.  Bilirubin is sensitive to light and oxygen, being easily bleached and chemically-degraded, even in vivo (as in the phototherapy of neonatal jaundice).

Bilirubin undergoes photoisomerism and then photooxidation on exposure to light resulting in more polar, readily excretable end products. (This was sciencebod's first research interest while employed as Research Specialist at the University of Pennsylvania Hospital Medical School, 1970-72)

A colorimetric test and other incidental “quickie” spot and tests does not suffice to identify bilirubin, nor is the pigment bright red, as claimed (it is orange). Nor do people become highly jaundiced as a result of trauma: distance runner's foot-strike haemolysis of blood cells (with consequent degradation of haemoglobin-derived porphyrins to biliverdin and bilirubin) produces mild not gross hyperbilirubinaemia, insufficient to alter the colour of blood.

33. Invoking bilirubin appears to be a means of evading the observation that the so-called blood stains would have long ceased to be intact haemoglobin, and are now “haematite”, which is iron(III) oxide, Fe2O3, probably hydrated with one or molecules of water. One would indeed have expected blood to degrade over centuries to inorganic constituents, aided by microbial action in moist air. 

      34. Reports that the blood is type AB, or have markers for male chromosomes, or genes for globins etc etc appear to be at best anecdotal, possibly apocryphal. DNA cloning by the DNA polymerase assay is notoriously sensitive to contamination with recent DNA, e.g. from sweat, fingerprints even,  with a few shed skin cells.

 35. Re hair: any high energy radiation capable of scorching either cellulose or a carbohydrate coating would have degraded hair as well – the latter being keratin, which is a protein. Hair is easily singed. The hair on the Shroud shows little by way of fine detail. Indeed, but for its location, it might not have been easily recognizable as hair.

36. Hungarian Pray manuscript. Said to show same L-shaped pattern of burn holes in the burial shroud. The cartoon-like line drawings show shroud immediately after the Resurrection. There is no emphasis given to holes – they are largely lost among the other markings gs.

The holes could just as well have been a nominal attempt to portray blood spots. The biblical account makes no mention of burn holes. If the creator of the Pray manuscript had meant those few holes to represent burn marks, would he not have added flames or wisps of smoke? 

37. There is much else said about the images on the Pray manuscript that has “the eye of faith”, e.g that Christ shows the same epsilon-mark  on forehead, as distinct maybe from an indistinct squiggle  or that the artist has attempted with his fat “plus signs” to portray a herring-bone weave. One can read far too much into a sketch that gives little if any indication that it was intended to be heavy on symbolism, especially when those alleged symbols like burn marks form no part of the biblical account, and which modern day observers and interpreters  intend merely to buttress speculation about the Shroud of Turin.

38. Conclusions so far:

The Shroud is too elaborate, contrived and stylised to be anything but a medieval fake.  Why have a magically-produced imprint of a crucified man energetic enough to chemically degrade cellulose and/or other cloth constituents, yet also replicating a checklist repertoire of scourge marks (overdone)  blood flows, crown of thorns,  nail exit wounds, etc etc.

It is incredible that modern man should be be speculating and/or fantasizing about miraculous flashes of intense high-energy electromagnetic radiation, indeed coherent laser-beam ultraviolet light . What started this nonsense? Answer: 20th century computer games (converting  faint 2D markings to 3D hologram-like images in what might be called upmarket computer games) together with "revealing" details (nails through wrist etc)  regardless of whether they agreed with the Biblical account or centuries of received wisdom.

It simply beggars belief that folk should fall for this combination of digital jiggerpokery and special pleading. The Shroud can be viewed as a medieval forerunner of Euro Disney – inspired by the same motive to create a spectacle and through it to flog a dream - and about as genuine as the latter’s ersatz fairytale castle.