Towards a new, more chemically-nuanced model for the Shroud of Turin (with hat tip to STURP’s Joseph Accetta). Think slow-release H2SO4, and maybe iron catalysis too.

 

 

*

There's generally scope for fine-tuning models in science...

Summary: What we see today is not what the putative 14th century fabricator of the Shroud intended us or rather his contemporaries  to see. The Mark1 image was a more prominent dye/mordant combination, essentially as proposed by STURP's Joseph Accetta, imprinted onto linen possibly to resemble dried, ancient sweat (with blood pre-additions too). (See earlier ideas onthis site re the Shroud being an attempt to produce a life-size rival to the fabled “Veil of Veronica”).  That Mark 1 Accetta image has largely if not entirely disappeared, as a result of natural wear and tear, bleaching by sunlight, detachment of mordant etc etc, possibly even laundering. What remains is a Mark 2 ghost image, still a negative “photograph-like” imprint, one that formed gradually under the dye mordant via chemical action that mimics the effect of scorching with a hot metal template.  The chemistry would be similar (dehydration, oxidation of linen carbohydrates) but achieved slowly at environmental temperatures by chemical reaction with or without catalysis. 

The chemicals used in medieval bleaching offer ample scope for modelling of slow superficial “scorching” of linen fibres, especially the acid mordants like aluminium and iron sulphates that easily hydrolyse initially to dilute sulphuric acid. The latter becomes steadily more concentrated when exposed to air due to progressive evaporation of water, the sulphuric acid being relatively involatile. and increasing concentration to largely anhydrous H2SO4 with a powerful dehydrating, caramelising and finally charring action on carbohydrates is well. Caveat (an afterthought):  It never becomes standard "concentrated" sulphuric acid (98%) however, which is what I call "The Beast" give its violent affinity for water, as witnessed by its ferocious charring of carbohydrates (see  photograph below). Why not? Because maximally concentrated 98% H2SO4 is highly hygroscopic: it picks up moisture from the air, increasing its volume considerably as it does so. It's self-evident therefore that dilute sulphuric acid can never evaporate all the way down to the 98% level when exposed to the air (ordinary moist air that is). It simply becomes more concentrated - though I can't as yet put a figure on it.

This is what concentrated sulphuric acid does quickly to cotton (wiki).  This blogger has placed an order for modern car battery acid (37% H2SO4) which will be used for observing the time-course on linen as water gradually evaporates off to leave conc. H2SO4. Might one see subtle sepia-coloured caramelization rather than charring? (Update: yes, but barely perceptible  if tested at room temperature: elevated temperatures are needed for clearly visible browning).

Catalysis of oxidation by iron salts is an added possibility, given the ability of variable-valency iron salts (Fe++ and Fe+++) to facilitate organic redox cycles, acting as intermediary electron acceptor/donors between atmospheric oxygen and oxidisable substrate.The traces of iron oxide that Walter McCrone and his microscope detected on the Shroud may not have been artist's red ochre, as was proposed, but oxidized iron mordant, e.g. iron (III) oxide-hydroxide, FeO(OH).H2O, more commonly written as Fe(OH)3. See the wiki entry.

More to follow (much more!) in short time-spaced instalments. Sorry, it's the way I work.


Still Thursday 19 March,  11:50

Sulphuric acid, H2SO4, the  most common mineral acid of commerce, with thousands of applications, has always lurked in the Shroud literature. Take this extract, for example, from the 1981 Summary of conclusions from the Shroud of Turin Research Project (STURP):

Quote (STURP 1981) : The scientific consensus is that the image was produced by something which resulted in oxidation, dehydration and conjugation of the polysaccharide structure of the microfibrils of the linen itself. Such changes can be duplicated in the laboratory by certain chemical and physical processes. A similar type of change in linen can be obtained by sulfuric acid or heat. However, there are no chemical or physical methods known which can account for the totality of the image, nor can any combination of physical, chemical, biological or medical circumstances explain the image adequately.


Sulphuric acid pops up again in that stunningly original and inventive attempt by Professor Luigi Garlaschelli and his students to model a Shroud-like image.  I shall look out his paper (a copy of which he sent me personally) and quote a few of his own words. In the meantime, here's a comment I left on Dan Porter's shroudstory site last summer that is highly germane to what follows:

Colin Berry

July 17, 2014 at 3:13 pm

Reply

Luigi Garlaschelli’s powder-rubbing model, even if incorrect, gives a pointer to the kind of subtlety that is possible if wishing to leave a “stamp” (good, straightforward term)
on linen.
He proposed that the kind of ochre (red-brown ferric oxide, Fe2O3, available in medieval times, made by decomposing green vitriol, hydrated ferrous sulphate, FeSO4. 7H2O), would have contained acidic impurities, notably sulphuric acid, which becomes conc H2SO4 when one drives off water.

He reckoned that the acidic ochre was used to produce a negative image from a human subject, and the linen then heated in an air oven to make it seem older than it really was. But the heat might also have caused the acidic impurities to chemically etch the linen, via the same kind of pyrolytic chemistry (dehydration reactions etc) that occurs when linen is scorched directly with a hot metal template. Later the solid ochre flaked off, or was scrubbed off, leaving just the ghostly image (Hugh Farey has also flagged up this kind of erosion scenario as a possible explanation).

In other words, there’s a mechanistic spectrum that runs between a purely thermal action (scorching from a hot template) or a chemical mechanism (traces of sulphuric acid etc) or any number of in-between mechanisms that rely on a combination of chemistry and heat.

Despite these uncertainties re precise mechanism, the narrative may hinge on the credibility or otherwise of a medieval artisan asking himself a simple question: “How can I produce a whole-body version of the Veil? How can I simulate a post-Criucifixion sweat imprint that might be left on linen as a yellow discoloration?”

It didn’t need to be a real sweat imprint – merely a yellow-brown image that could be represented as an ancient degraded sweat image.

My own preferred scenario is that of a post 1314 scorch-imprint designed to simulate a slow-roasted Knight Templar, possibly a Knight Templar (Jacques de Molay?) being “reinvented” as a sweat imprint of the crucified Jesus.

Then there was my stumbling for the first time on the unique approach of STURP's Joseph Accetta. PhD.
Yup, that's Joseph Accetta PhD, electro-optics/laser/imaging expert, not to be confused with another Shroud researcher - August Accetta MD.

Again, it saves time if I simply cut-and-paste a comment I posted to shroudstory in June 2014, with the key passage from Accetta's 2008 Ohio Shroud conference referring to H2SO4 highlighted in red:
 

colinsberry

June 5, 2014 at 12:55 pm

Reply

Try downloading this PowerPoint presentation from Joseph Accetta, David (he being the subject of a recent posting here, and one of STURP’s genuinely scientific, non-agenda driven, non grandstanding participants in my view).


Go to the last few pages (approx 24/25). There you will see model spectroscopic (ir) studies not just with thermally-imprinted scorches, but also with linen that has been chemically dehydrated with 36% H2SO4 and even your invisible ink (lemon juice).

I’d be the first to admit there may be little to distinguish between an image produced by chemical as distinct from thermal dehydration (especially if chemical action was heat-assisted – see Luigi Garlaschelli’s model ‘frottage’ imprinting with acid-contaminated red iron oxide). It’s the vehicle for acid that is important (not too runny, not too viscous).

Some of us eagerly await details of what JA will say at St.Louis. Let’s hope it receives more attention than his meticulous and detailed studies to date.

Nuff said. I’m thinking of doing a post dedicated entirely to JA (he being my kind of scientist).

Still Thursday, 12:50

We then learned that this STURP veteran was scheduled to present a paper at the October 2015 St.Louis Shroud conference. What would he say? What was his current focus, some 35 years on from that celebrated  week in intense activity in Turin?

Well, here was the abstract he submitted for the St.Louis meeting.

Abstract:

This paper is based on the assumption that the Shroud is of 14th century origins consistent with its radiocarbon date and thus must be explained within the technology and historical context of that era. Avoiding the controversy surrounding the date, the author presents a plausibility argument to reconcile its visual and forensic properties with extent 14th century printing technology, geographical circumstance and historical context. The observed 3-d properties of the image are discussed in relationship to physical image formation processes and a plausible explanation for this extraordinary effect is given based printing techniques known to exist at that time and in that locale. Further the argument is reinforced with analytical results showing that under any reasonable assumption about the surface bi-directional reflectance distribution function (BRDF) including the use of measured human skin data, the observed 3-d properties cannot be reconciled with any known radiative imaging process and thus must be a contact process. 

 No further) references (as yet) to H2SO4 note, But there was that intriguing allusion to "printing techniques". What was that about? Had anyone mentioned printing before (barring my preferred scorch imprinting)? Hadn't STURP excluded not just artists' pigments, but inks and dyes too? What did this Joseph Accetta have up his sleeve?

Here it is: Origins of a 14th Century Turin Shroud Image (pdf)

First, the disappointing feature. There's no further mention of sulphuric acid. Indeed, there's only a single reference when one searches "acid" - to tannic acid.

But acids, or at any rate "corrosive" agents,  are implicated, and importantly it seems, in this intriguing passage, one that sets the tone for an entire new slant (at least that this blogger is aware of) on the possible origins of the 'enigmatic' Shroud image:

"Iron gallate and carbon inks of which there are reportedly several hundred recipes are seemingly plausible candidates for coloring agents because they were the ink of choice during the medieval period and could be made sufficiently viscous with gum Arabic, linseed oil or a number other binders to serve as suitable colorant for textiles. It should be noted that the penetration of the colorant into the textile was not a primary consideration during the printing process because mechanical stresses would have flaked almost all of the ink away. Many of these formulations are corrosive and would have over time either caused cellulosic degradation or reacted with some other substance on the linen such as a mordant or starch.  Some of these inks are known to create time dependent contrast effects depending on the formulation and there are several hundred papers dealing with the conservation issues on rare documents relative to these inks."

So what are these corrosive agents? Are they the dyes themselves, or the mordants that attach them to cloth? Why would corrosive action be necessary? Dyes are dyes, surely, that can be used to imprint an image without having corrosive action, the latter being unnecessary and undesirable surely?

Accetta has also put his St.Louis slide presentation online.

There are details there that are not in the pdf:

So the original image was prominent. What we see today is a degraded image. Presumably the corrosive ink (iron gall?) was corrosive and contributed to the degradation. Does that narrative fit with what we know about the TS image, notably the lack of reverse (aka obverse) side image? Would not inks or other soluble dyes penetrate, even if thickened with gum arabic or some other viscosity-increasing agent? Would not some of that cross-over have survived to be spotted and reported on by STURP and others?

Before addressing those issues in more detail, reference must be made to another slide in Accetta's presentation , alluding to work done by a French group on the stability of medieval documents written in the standard iron gall ink:

Here's a cut and paste from the slide:

FTIR techniques applied to iron gall inked damaged paper

REMAZEILLES Céline, QUILLET Véronique , BERNARD Jacky LEMMA, Université de La Rochelle

INTRODUCTION

Iron gall ink corrosion of paper is one of the largest threat for our graphic patrimony. A great work has been done in this field to explain the possible mechanism of paper degradation and to propose  curative methods  The main degradation mechanism proposed in the literature is the following : iron gall ink prepared with different ingredients including tannins and vitriol causes both acidic hydrolysis and Fe2+catalysed oxidation of cellulose. Paper turns brown and loses its mechanical properties. Yet the great variety of iron gall ink recipes , and the great variety of visual aspects of manuscripts suggest that many side effects could occur and contribute to the different aspects of paper degradation (colour changes, halos, mechanical properties). 
...

So, whilst one has to look quite hard, there are two additional gems of information in that French paper - first the reference to "vitriol"  (SULPHURIC ACID) lacking in the main presentation AND the recognition that iron salts are capable of catalysing redox reactions sufficient to oxidize chemically inert cellulose (though that need not be the target polymer in linen, despite being the major constituent - there being more sensitive ones, notably the hemicelluloses of the superficial primary cell wall).

Time now to put cards on the table. First, this blogger suspects that Accetta with some French back-up was right: the Shroud image began life as wet imprint - not the dry scorch imprint that has been my model thus far (though its proved handy in de-mystifying the negative image and, especially, 3D properties). Iron gall ink, with its mixture of plant tannins and iron salt mordants serves as a handy model for the imprinting medium - but no more. Any number of soluble dyes could have been used, probably mordant-assisted, e.g. with commonplace alum (potassium aluminium sulpahe) or with iron or chromium salts. But here's where I diverge from Accetta. He thinks the corrosive agents, whatever they might be (mordants? vitriol?) partially degraded the original image. leaving a remnant that we still see today. I beg to differ. I consider that the entire dye/mordant combination has vanished entirely, for a combination of physical and chemical reasons (crumbling away, bleaching by sunlight, loss on laundering, however infrequent). But we still see a 'ghost' image that is NOT the original. Here's a schematic as visual aid:



 

3 stages in formation of the present ghost image on the Turin Shroud, with disappearance of the initial more prominent dye/mordant image

What in a generic sense could have produced a secondary 'ghost' image, probably quite slowly, but fast enough (decades, centuries) such that when the primary Mark 1 dye/mordant image  has faded from a view a faint but STABLE ghost is revealed?

There are two candidates, close chemical cousins with similar properties, that are in the frame. One is alum, with aluminium sulphate as 'active ingredient',  that is well known for releasing SULPHURIC ACID in solution or exposed to moist air, due to chemical hydrolysis:

aluminium sulphate + water ->  colloidal aluminium hydroxide (the true dye-binding mordant) + sulphuric acid

Al2(SO4)3  +  6H2O  ->  2Al(OH)3 +  3H2SO4 

 

 (Aluminium hydroxide can also be regarded and/or named as hydrated aluminium oxide, the two being equivalent in terms of atomic makeup)

But there's the iron, at least in iron gall ink.  How did it get there? It could have been added as green vitriol, aka ferrous sulphate, aka iron (II) sulphate, FeSO4.7H20. There are other more rustic ways of introducing iron, even as elemental iron and crude vitriol (sulphuric acid). In time, it oxidizes in air to orange-brown ferric sulphate aka iron (III) sulphate. That plays different roles, depending on whether it's an adjunct for use with an ink (e.g. oak gall) or a plant dye for fabric printing. In ink, it helps give a darker colour, quickly visible. In fabric-dyeing it acts as a mordant, in addition to effects on colour, which can vary, and serves as a mordant for the same reasons as alum above. Why? Because it also undergoes an analogous hydrolysis in water, producing iron hydroxide, aka iron oxide-hydroxide, the true mordant AND again that ubiquitous SULPHURIC ACID that have can have other actions, whether intended or otherwise:

 Fe2(SO4)3  +  6H2O  ->  2Fe(OH)3 +  3H2SO4

Let's suppose for the sake of simplicity that a plant-dye had been used with alum as mordant. The mordant would have attached the dye firmly to the fabric, but not prevented bleaching and other deterioration of the colour over decades and centuries. Meanwhile any alum excess in the cloth could have slowly released sulphuric acid which , acting on the superficial linen fibres under the dye -coating, would (or could) have generated a ghost image , invisible to the first cohorts of pilgrim spectators. However, one is relying purely on H2SO4 to degrade the linen fibres. It can do that via chemical dehydration, at least in principle. But scorching of linen, whether by thermal or chemical means, is generally assumed to require oxidation as well as dehydration. STURP acknowledged as much in its 1981 summary. Maybe it assumed that atmospheric oxygen would produce the oxidation (cold sulphuric acid alone is unlikely to result in oxidation). But contrary to popular belief, atmospheric oxygen is not very reactive chemically, due to its triplet electronic state, which is why one has to raise temperature to kick-start combustion and other oxidation reactions. Organic compounds, even complex ones, can often survive indefinitely if there's no flame or other source of ignition. That's where iron salts come in handy if one is wishing to implicate atmospheric oxygen as the ultimate oxidant - they CATALYSE oxidative reactions, as those French workers recognized. Why? How?

Well, let's not turn this posting into a chemistry lesson. Suffice it to say that iron, unlike aluminium, can exist in solution as Fe++or Fe+++. The first can act as a reducing agent by donating an electron to an organic or other compound ( like linen carbohydrate!) become Fe+++, and the second as an oxidizing agent by accepting an electron. One can have s0-called redox cycles, in which iron shuttles between the two forms, using atmospheric oxygen to convert any temporary surplus of Fe++ back to the oxidizing Fe+++.

One would not be so focused on iron if it were not for the fact that Walter McCrone discovered flecks of iron (III) oxide on sticky-tape samples of Shroud fibres supplied to him by Raymond Rogers. He assumed it was artists' red ochre, and quickly dismissed the TS as a medieval painting. But the iron oxide's crystallinity suggested it was too pure to be artist's pigment (often ground up natural mineral in medieval times and thus impure). Might it have been iron oxide that formed from use of an iron mordant in dyeing, or, as Accetta would prefer, as an adjunct in oak gall ink or similar?
If iron had been present, for whatever reason, it greatly increases the probability of converting linen to yellow or sepia products resembling a superficial scorch, because the probability of there being oxidation as well as dehydration is greatly increased. What's more, the iron does not get used up if the redox cycle is linked to atmospheric oxygen  as ultimate electron acceptor, becoming oxide or hydroxide ions. In other words, the oxidation can be CATALYSED  by mere traces of iron that cycles between its two valence states. 

So we have a new model to explain why the TS image looks the way it does - faint, almost to the point of invisibility, at least close-up, because it's not the Mark 1 image we see, but a ghost left by acid and/or iron impurities in the putative dyes and mordant mixes. That ghost is a kind of chemically scorched or 'caramelized' carbohydrate.

Are there features of the Shroud image that are not explained?

Fluorescence under ultraviolet light, or rather lack thereof?

Fluorescence was always the Achilles heel of the dry thermal scorch imprint model. Thermal scorches fluoresce, we are told, at least the 1532 "scorch" margins on the TS, while the TS body image does not. What about chemically-induced scorches? Well, there's some confort to be had from Luigi Garlaschelli's modelling of the Shroud image, using metal oxides in slurry form with added acids (sulphuric included) as imprinting medium. The final images did NOT fluoresce (he was keen for us to know that).


What about image superficiality (allegedly 200-600nm in thickness )? What about ease of 'strippability' with adhesive tapes? What about mechanical strength of image-bearing fibres? What about the claimed blood first-image second chronology/ Can that be better accommodated in the H2SO4 and/or iron model? (yes, I believe it can). Nature of the template? Woodcut? Customised one-off, or one that if preserved would be recognized as consistent with art history or early attempts at fabric printing? Did it really need to be wood? Might not easily mouldable clay have been a more convenient material for a one-off, and then quickly hammered into small pieces, destroying the only evidence as to method of manufacture?

More to follow. But that's enough for one day methinks. Experimental testing? A start has been made, and more chemicals are on order (sulphuric acid, iron sulphates, gum arabic).

Freshly-prepared extract of pomegranate rind/pith, boiled down to thin syrup.

Having no easy access to oak galls, I'm using pomegranate rind/pith to make a syrupy extract of yellow tannins, with or without alum as mordant that can be painted onto bas relief templates to get imprints. (Yes, they are tone-reversed negatives, needless to say, and respond reasonably well to 3D enhancement). See the blog posting that precedes this one for preliminary results.

Friday 20 March

Before discussing anything else, let's see how this double imprint, fast dye/slow chemical scorch mechanism offers an explanation for that "blood first/image second" finding of Adler and Heller. I allude to their experiment with the protease in which blood proteins were digested off TS linen fibres with proteolytic enzymes to reveal colorless fibres underneath. That finding has always been an embarrassment for those of us who provisionally accept the radiocarbon dating, warts an' all (while wondering why there was no Phase 2 sampling from additional sites). How could a forger know where to paint on bloodstains if the linen had initially been image-free? OK, here's an explanation, or at any rate a get-out- of- jail-free card. The blood was NOT painted on first. The image was dye-imprinted, and the blood painted on top (the easy way). Then the Mark2 image gradually formed under the dye imprint, due to chemical action on the linen carbohydrates. But that did NOT happen where there was blood overlying the body image. Why not? Because the reactive chemicals (H2SO4, iron salts etc) had an easier substrate ON TOP than underneath with which to react, so were constantly mopped up by that overlying blood leaving the linen fibres in their original pristine condition. So when STURP scientists came along centuries later and digested away the blood to find those pristine linen fibres exposed, they quite reasonably supposed that the blood was acquired first, not second. They weren't to know that there had originally been a long-gone Mark1 dye-imprint between blood and Mark2 chemical scorch, were they?
Thought-provoking quote on this morning's BBC site under an article headed : "Can Religion and Science Bury the Hatchet?"

"'Simplistic' distinctions
 

"The old distinction that science is about facts and religious belief is about faith is far too simplistic," says Prof Wilkinson.

"Science involves evidence, but it also involves skills of judgement, and skills of assessing evidence.

"After all, you only have a limited amount of evidence to base your theory, and you have to trust your evidence - which isn't far from being Christian.

"It doesn't involve blind faith - and indeed religion is not good religion if it is simply based on blind faith.

"Christianity has to be open to interpretation about its claims about the world and experience."

For Prof Wilkinson, the two are absolutely not mutually exclusive."

Interestingly, just yesterday I came across a site for secondary teachers in England and Wales that has "Understanding Science 101" in the title bar (yes, really). There's some amazingly perceptive stuff in there that one rarely meets elsewhere. It should be required reading for anyone who is not a scientist, but thinks they know and understand how science operates and makes progress - or tries to, or who imagines that just anyone can do science. The expression "they don't know the half of it" springs to mind. This blogger is a 70 year old retired scientist, but is still learning more about dos and donts of research strategy with each new passing day. Might he have arrived where he is now but much sooner?

Back to practicalities: what about that suggestion from last night - using moulded clay instead of  Accetta's carved/engraved woodcut as template for dye/ink imprinting?

If clay, did it need to look like this?

It's taken from the Home Page of Rolfe's Enigma site (see previous posting for this blogger's view on those allegedly  'enigmatic' features that are supposed to equate on suspects with 'unique', but don't really). Yes, I realize I've been a bit mischievous in using that image, which in the Rolfe narrative would be a model derived from scanning the Shroud image, not a model used in reverse to make it! (We'll overlook the small matter of it having complete arms, as if there had been no 1532 fire)

Now then, if you, dear reader, had been a medieval artisan supplied with a cartload of wet clay and been told to fashion a life-size effigy of the lifeless Jesus recently taken down from the cross, would you have attempted to reproduce the above?  Suppose you had a rough idea about how the imprint was to made, e.g. by painting dye onto the highest features of the relief, then spreading linen on top, then manually pressing the linen into all the hollows and crevices to get best most intimate contact between template and fabric. Would you have then proceeded to mould (or attempt to mould) a fully 3D effigy. The answer is obvious - NO. It's impractical to do that. Wet clay, whilst stiff, would not allow one to do that - gravity would cause sagging of those parts not in contact with the supporting surface. But here's the crucial point. One does not need a fully 3D effigy. A bas relief is sufficient, or rather two, one for frontal, one for dorsal side, if one look  at the Shroud. There are no sides! Indeed, that's just as well, since any attempt to imprint off the sides of that effigy one sees above would introduce lateral distortion.

Take away message: not only was wet clay (later left to set) the likely template material. It was fashioned as two separate bas relief templates, one frontal, the other dorsal. That incidentally would account for why one is said to be some 7cm taller/longer than the other (the source of much 'creative accounting' on the part of the pro-authenticity tendency that need not concern us right now).

Might there be practical difficulties in imprinting off a clay bas relief template instead of woodcut? It's a moot point. I shall try to get hold of modelling clay and do some crude experiments to see how well the dye/mordant mix sticks to the template and how well it then transfers to linen. Having already experimented with metal templates in dye as well as scorch-imprinting, I'm not expecting there to be insuperable problems, especially as there's the possibility of making additions, e.g. soap or other wetting agents etc.that might improve the outcome.

It's the imprinting off a bas relief, or less probably fully 3D template that generates the image with negative (dark/light reversed) properties AND reasonable response in 3D-rendering progeams like ImageJ. It shouldn't be necessary to have to say this in 2015, but still we have to endure lectures from so-called historians (with amazing blindspots for the historical record) telling us the Shroud is just a degraded painting or that we have overlooked the effects of ageing, wear and tear etc.  (Not so. Some of us, notably Hugh Farey and myself have been exchanging views on bloodstain and image-fibre attrition for YEARS.) This might be a good point at which to slip in a couple of cut-and-paste items of historical interest and relevance.


Here for starters is the celebrated, some say suspect d'Arcis memorandum, kindly translated initially from the medieval Latin into the French you see here (red) and a DIY-makeover (black) of the Google translation. We're told emphatically by a self-styled academic historian that no one in the 14th century would have been taken in by claims for the Shroud being the authentic burial cloth of Jesus. Is that the impression one gets from reading this?

From the letter of Bishop Pierre d'Arcis, addressed to Pope Clement VII, residing in Avignon (Letter written in 1389):

http://andreadicaffa02.unblog.fr/2011/08/05/

« L’affaire, Saint Père, se présente ainsi. Depuis quelque temps dans ce diocèse de Troyes, le doyen 
"The case, Holy Father, is as follows. For some time in the diocese of Troyes, the dean 
 

d’une certaine église collégiale, à savoir celle de Lirey, faussement et mensongèrement, consumé par la
of a certain collegiate church, namely that of Lirey, falsely and untruthfully,  consumed by the 
 

passion de l’avarice, animé non par quelque motif de dévotion mais uniquement de profit, s’est procuré 
 passion of avarice, driven not by any reason of devotion but only of profit, procured

 pour son église un certain linge habilement peint sur lequel, par une adroite prestidigitation, était la 
for his church a certain cloth cleverly/cunningly painted on which, by a clever sleight of hand, was 
 

 représentée la double image d’un homme, c’est-à-dire le dos et le devant, le doyen déclarant et  

shown the double image of a man, that is to say the back and the front,  the dean declaring and

prétendant menteusement que c’était le véritable suaire dans lequel notre Sauveur Jésus-Christ avait 
claiming untruthfully that it was the true burial shroud in which our Saviour Jesus Christ had

 été enveloppé dans le tombeau, et sur lequel le portrait de Sauveur était resté imprimé avec les plaies 

been wrapped inside the tomb, on which the Saviour's portrait had been imprinted with the wounds 

qu’il portait.
that he bore.

 [...] En outre, pour attirer les foules afin de leur extorquer sournoisement de l’argent,    
In addition, to draw crowds for the purpose of extorting money slyly, 

 

 de prétendus miracles ont eu lieu, certains hommes étant loués afin de se donner pour guéris 
 so as to claim that miracles have occurred, using hired men as to make it appear they had 

  

 lors de l’exposition du suaire, dont chacun croit qu’il est le suaire de Notre-Seigneur. 
 been cured upon exposure of the shroud, each convinced it is the shroud of Our Lord.

Mgr Henri de  Poitiers  de pieuse mémoire, alors évêque de Troyes, étant mis au courant de ces faits
 Bishop Henri de Poitiers of pious renown, then bishop of Troyes, being made aware of these facts 

 et pressé d’agir par de nombreuses personnes prudentes, comme c’était en effet son devoir
 and urged to act by many responsible people, as was indeed his duty 

sa juridiction ordinaire, se mit à l’oeuvre pour découvrir la vérité dans cette affaire.

in the exercise of his ordinary jurisdiction, set to work to uncover the truth in this matter.

Car beaucoup de théologiens et de personnes visées déclaraient qu’il ne pouvait s’agir
 For many theologians and persons who were consulted (had) declared that it could not be

 du suaire authentique de Notre-Seigneur dont le portrait se serait ainsi imprimé dessus,
the authentic shroud of Our Lord whose likeness had been imprinted upon it, 

puisque les saints Evangiles faisaient pas mention d’une telle impression, alors que si elle s’était produite,
as holy Gospels did not mention such an impression, whereas if it had occurred,
 
il semblait bien évident que les saints évangélistes n’auraient pas omis de le rapporter,
it seemed obvious that the Evangelists would not have omitted to report it,

  En fin de compte, après avoir déployé une grande diligence dans son enquête et ses interrogatoires,

In the end, after a thorough investigation  and interrogation, 

et que le fait ne serait pas demeuré  caché jusqu’à nos jours.
and that the fact would not remained hidden until today.

il a découvert la fraude et comment ledit linge avait été astucieusement peint,

he discovered the fraud and how the said cloth had been cunningly painted,  

 la vérité étant attestée par l’artiste qui l’a peint, autrement dit que c’était une oeuvre due au talent d’un 
 the truth being attested by the artist who painted it, namely that it was the talented work of said
 

homme, et non point miraculeusement forgée ou octroyée par grâce divine»
man, and not miraculously wrought or bestowed by divine grace "

(Texte latin reproduit par U. Chevalier, Etude critique sur l’origine du Saint Suaire de Lirey-Chambéry-Turin, 1900, Annexe, document G, p. VII-VIII).

(Latin text reproduced by U. Chevalier, Critical study on the origin of the Shroud of Lirey-Chambéry-Turin, 1900 Annex G, p. VII-VIII).

xxxxxx   (expect a few carefully-chosen words to appear here later).

Then there's this passage from Barrie Schwortz's shroud.com site (history page). I'll quote it in full, so as not to deprive readers of essential context, but the crucial few words come right at the end (highlighted in red):

April 14, 1503 Good Friday: Exposition of the Shroud at Bourg-en-Bresse for Archduke Philip the Handsome, grand-master of Flanders, on his return from a journey to Spain. The Shroud, which has been specially brought from Chambéry, with great ceremony, by Duke Philibert of Savoy and Duchess Marguerite, is exposed on an altar in one of the great halls of the Duke's palace. Savoy courtier Antoine de Lalaing records of the events of that day: "The day of the great and holy Friday, the Passion was preached in Monsignor's chapel by his confessor, the duke and duchess attending. Then they went with great devotion to the market halls of the town, where a great number of people heard the Passion preached by a Cordeilier. After that three bishops showed to the public the Holy Shroud of Our Lord Jesus Christ, and after the service it was shown in Monsignor's chapel." Lalaing adds that the Shroud's authenticity has been confirmed by its having been tried by fire, boiled in oil, laundered many times 'but it was not possible to efface or remove the imprint and image.'


This blogger has previously  taken that  account with a pinch of salt. But he'd now reconsidering in the light of the new model, when a Mark 1 image may have been gradually fading from view some 150 years after manufacture, but a ghost Mark2 image was being seen to take its place. Is it not perhaps unsurprising that an attempt would be made to achieve uniformity by speeding the removal of the degraded Mark1 image, especially if cautious testing had determined that the Mark2 image, while faint, was a lot more permanent and resistant to removal?  Why would that be? This little experiment with bleach and a thermal scorch may give a clue:

Top half: thermal scorches untreated. Lower half: excised portions of same scorches after steeping in bleach for 1 hour.

Close-up view of above

Those thermal scorches are not totally resistant to the bleach, though some of the loss may be due to mechanical effects (breaking off due to swelling of fibres). Irrespective, it's clear that thermal scorches can at least partly resist a harsh chemical like bleach, when the same agent decolorises my pomegranate dye extracts within a few minutes at most. Is it a mistake to imagine that a chemical scorch producing the hypothesized Mark2 ghost image has a similar chemical make-up to the thermal one above, i.e. dehydrated and oxidized linen carbohydrates, and while fainter than the Mark1 image is essentially permanent, resisting atmospheric oxygen, moisture, acidic pollutants etc and thus still visible (just) after many centuries, despite fires and the alleged treatments described above by courtier Lalaing?


Next experiment?

Linen, pomegranate, gum arabic crystals and bas relief template

Watch this space.

OK, that didn't take too long. The imprinting medium was pomegranate extract, alum and gum arabic. The template was painted iron, with some interesting rust patches even after giving a coat of metal undercoat. A litle iron does not hurt in this ranging shot experiment (see title). The imprinting was done two ways, using methodology developed in my earlier heat scorch experiments: LUWU (Linen Underneath with Underlay) and LOTTO (Linen On Top with Overlay).

That's the template being removed in the LUWU configuration; the completed imprint on the right was performed using LOTTO (see above).

More later, but please remember: what you see above are only the primary Mark1 images. They are of no relevance to the present TS image if, as hypothesized, we are now seeing only the secondary Mark2 ghost images formed by slow chemical action of dye/mordant imprinting chemicals, e.g. alum, sulphuric acid, iron salts etc., the Mark 1 image having disappeared long ago.

This posting is long enough as it is: so don't be surprised to see a new posting in due course in which the above images are tone-reversed and 3D-rendered, simply to see how well they compare with the thermal scorches. They will then be put away for months, maybe years to monitor the effects of time.

Afterthought: there's a major problem still to be addressed with the new model - the 'reverse side'. Even with the viscosity aid recommended by Accetta (gum arabic) there was extensive reverse side imaging.

Reverse side Mark1 images. Yes, they might disappear with time, maybe decades, maybe centuries, but would they not leave Mark 2 images on that same reverse side, which are NOT a feature of the TS?

 Pigment/mordant on the reverse side should surely generate a reverse-side Mark 2 image in the fullness of time - as acknowledged at least nominally in the earlier graphic. Can the problem be resolved? Maybe. The linen used in this experiment was very thin compared with others used in this ongoing project. Maybe viscosity aids like gum arabic* are not sufficient. Maybe the interstices of the weave need to be plugged with a cement-like substance. But with what? Dare on suggest that there's a potential role here for Rogers' starch* - not as a technological weaving aid, but as aid to unilateral printing. Would that be raw starch, with intact discrete starch granules, or gelatinized starch, with dispersed starch?  Granted, adding starch to the formulation introduces yet another ingredient, another variable, another complication, and the inevitable references to Occam's razor. But there's a upside too - if there were a starch 'skin' on the linen first, then a second aspect of the TS image can be explained, namely Rogers' observation that the image layer can be stripped off, and is exceedingly thin (estimated at 200-600nm based on failure to see in cross-section under a light microscope). In this scenario, the Mark 1 image layer could be on a starch coating, or linen fibres or both, with mordant acting as a bridge between dye and binding substrate. Where would the Mark 2 image form?  Starch? Fibres? At least the model offers possibilities for testing these alternatives using adhesive tape, microscopy etc, essentially as deployed by Rogers and his STURP colleagues.

 It was the reverse side problem that persuaded this blogger against going down the soluble dye road, to say nothing of STURP's failure to link the body image with external pigments of any kind, and instead to focus on thermal scorching. The latter coudl be said to be 'on the back burner' while the strengths and weaknesses of the current dye/mordant model are investigated more thoroughly, especially when  assisted by starch, viscosity agents etc if able to prevent dye migration across the weave,

* Here's what Joseph Accetta  had to say re starch and gum arabic in his St.Louis paper (I've corrected his spelling of 'Rogers').

We could speculate that the starch likely present in the cloth reacted with the gallate ink rather then the cellulose itself. Gum Arabic which is a complex and variable mixture of arabinogalactan oligosaccharides, polysaccharides and glycoproteins and a common binder for coloring agents and may have been responsible for the effect observed by Rogers and Adler that the sepia coloring agent literally peeled off from the fiber leaving only the uncolored underlying fiber however no protein in the image areas was found . The initial protein may be bound chemically in ways not amenable to test . In summary, there is a relatively wide range of chemical reactions that that have not been investigated and further the colored fibrils should be subjected to all of the means of modern analytical techniques to specifically define the molecular composition of the coloring and this will require attendant access to the cloth for further sampling.

Is the Shroud of Turin image really "enigmatic"? See this straightforward, no-nonsense modelling exercise.

There be more where this came from - read on if you dare

One often sees or hears the Shroud image being referred to as “enigmatic”. 

Adjective: enigmatic

"Difficult to interpret or understand; mysterious."

Indeed, there's even a "Shroudie" site (and they don't come much Shroudier!) that calls itself "Shroud Enigma".

A "Multifaceted" Enigma, no less...

Given that the TS is thought by some to depict the actual image of the crucified Jesus on his burial Shroud from 2000 years ago, it’s perhaps not surprising that some have read “enigmatic” to mean not just "mysterious" but “supernatural”.

Personally. this retired science bod is quite happy to entertain the possibility of certain phenomena being supernatural, but only if non-supernatural explanations have been carefully considered and rigorously excluded.. Thus I'm minded to think that the "Big Bang" was the work of a supernatural entity - though that has not prevented me proposing a non-supernatural explanation (see margin notes) that uses conventional physics. 

Rigorous filtering out of non-supernatural explanations is sadly not the case where the Turin Shroud is concerned -  there being little real science and a surfeit of pseudo-science aka tosh.. One has only to peruse the headlines that have appeared from scientists ("scientists"?) in recent  years.  Try googling  turin shroud to find entries like this one which as it happens was what sparked my own (renewed) interest in the Shroud, after lying dormant since the 1988/9 radiocarbon dating.

If the radiocarbon dating is correct (yes, it needs confirming with a wider range of sampling sites) then the Shroud is not 2000 years old, but more like 650 years, give or take, with a birth date round about the first recorded showing of the TS at Lirey, in the rolling plains of the Champagne region of France in 1357 approx.

 Let’s suppose it is medieval. Then how come the image is “enigmatic” if man-made, not supernatural?  What features cause it to have acquired that tag, and why has science allegedly been unable to explain its peculiarity, far less to model it in the laboratory? Or can it? Is it really “enigmatic”? Or is that self-serving hype, the kind to which TV documentary makers are so enamoured?

Those seeking a comprehensive review of all the peculiarities of the Shroud image, whether real and authenticated, or claimed and maybe not well established, are in for a bit of a surprise and maybe disappointment. You see, this posting focuses on just 4 features.  What’s more they are the headline features-  the same ones about which millions of words have already been written. I refer to:

1.  “negative” photographic character

2.  its “non-directional” character (no obvious source of angled illumination, with resulting shadow bias, no brush strokes etc).

3.   its “encoded 3D” properties,

4.   its (alleged) extreme superficiality.

These are all the so-called “macroscopic” properties. I shall say nothing for now about “microscopic” properties (see same link), or about fluorescence, or lack thereof, for reasons that I’ll discuss in another posting. Suffice it to say that this blogger is somewhat dubious about claims for microscopic fibre characteristics that are (apparently) not based on viewing teased-out individual fibres, but upon entire skeins of bunched-up fibres, as in the Mark Evans photomicrographs. Good photos, yes, but not fit for purpose re 'microscopic' image characteristics. Nuff said.

So what could this humble blogger have to say that has not already been said, in many instances more eloquently?

Well, we’re told it’s not what you do, it’s the way that you do it, or, rehashed, it’s not what you review, but the way that you review it. I’m going to review the 4  chief features of the Shroud without a single image of the Shroud itself! Why? Well, I hope the reasons will become clear.

Why adopt this approach?  Answer: it’s an attempt to keep the polemics on the back burner (and of polemics there’s plenty, indeed a surfeit in sindonology (or shroudology as I prefer to call it). Let’s re-examine the “enigmatic” nature of the TS image, especially its headline features, and do so dispassionately.  At each step of the way, let’s ask ourselves this. Are they really as enigmatic as claimed? Oops. A polemical edge is already starting to intrude, so let’s go straight now to the step-by-step processes that have been used to analyse the Shroud image, but choose a model system that is stripped of emotive imagery. Let’s take the Shroud out of shroudology..  Let’s see how a different image responds, indeed an entirely synthetic, unquestionably  “ man-made” one. Let’s ask whether the adjective “enigmatic” would ever be applied to the image transformations that you are now about to see.

Starter image: I wanted one of a rubber stamp with lettering. But not a real one, at least not initially. (See tail end  for quickie test with a real date stamp). Why start with a make-believe stamp?

1. Because I wanted the raised lettering to appear white on a dark background (real ones usyally have black or coloured rubber) so as to start with what unequivocally is a POSITIVE image. (highest relief is lightest part of the image, due to unobstructed light reflection).

2. Because I wanted the lettering to be the “right way round” initially, not reversed as on a real-life rubber stamp.

This 3D template, designed for imprinting a 2D image of itself, would first be used to create an imprint of itself. The latter would then be taken through the same sequence of steps to which the TS image has famously been taken, starting with a simulation of Secondo Pia’s positive-to-negative conversion, followed by 3D-rendering. The process would then be played backwards, looking separately at reversion from negative to positive AND reversion of left/right "mirror image" changes. 

 Put like this it may seem excessively laboured.  In fact it’s anything but, we shall see, simply  by letting the pictures tell their own story, with minimalist captions.

I shall now post the graphics, then hit the "Post" key. My own interpretation (and hopefully that of others) can wait till tomorrow or later.

Fig.1 This image is not a real rubber stamp, needless to say, but made using ImageJ to look like one. It's entirely man-made, deliberately so, to be used as a 'thought experiment' in what follows.

Fig.2. Imagine the "rubber stamp" was coated with black ink. Here's how the imprint would look. It's light/dark reversed (like a photographic negative, though not one).  It's also left-right reversed - like a 'mirror image'.  However, those two features can be easily separated, arising  as they do for different reasons

Fig.3  As I say, negative image and mirror image are not inseparable (see above). One can easily restore the initial left-right configuration with photoediting software (ImageJ used here) while retaining the negative image.

Fig.4  To press home the point that negative and mirror images are not one and the same thing, even if happening together in the same imprinting operation, here's an image in which the original positive character has been restored, again in ImageJ, while preserving the reversed (mirror) image.

Fig.5. So far I have modelled the result of employing black ink on the "rubber stamp", making it easier to produce comparisons with photographic negatives. But the Shroud image is not black but faint yellowish brown. It's as if our rubber stamp had been coated with that colour instead of black.

Fig.6 But let's not allow the discussion to get too coloured (literally!) with Shroud imagery. To stay on the scientific straight and narrow, let's recall that any coloured image can be easily converted to 'gray scale' to avoid complications, that yellow above becoming grey, rather than jet black.

Fig.7: One can always use a photoediting program to convert grey into jet black, so as to reduce still further the possibility of a coloured (yellow or other non-black) imprint behaving unpredictably in further image processing.

Fig.8 So what started as a yellow-brown rather than black imprint has now been converted to one that is virtually indistinguishable from the black imprint of Fig 2, especially as it has now had a left-right flip too. Any enigmas so far?

Fig.9: Goodness gracious! What has happened here? I've taken the yellow-brown imprint, uncorrected mirror image, and put it into ImageJ's 3D rendering program. I've pretended I knew nothing about the original 3D of Fig 1, and simply adjusted settings arbitrarily to get a huge 3D response.

Fig 10:  As I say, the settings are entirely arbitrary if one knows nothing about the original template from which the imprint was obtained. In the case of the Shroud, it  could have been fully 3D in a pro-authenticity model, or much flatter, like a bas relief, in a medieval scenario. Here the settings in ImageJ have been reduced to give an "embossed look" with minimal 3D rendering.

Longstanding quote from the sidebar  of Dan Porter's shroudstory.com: my bolding

"No one has a good idea how front and back images of a crucified man came to be on the cloth. Yes, it is possible to create images that look similar. But no one has created images that match the chemistry, peculiar superficiality and profoundly mysterious three-dimensional information content of the images on the Shroud."

Er, what's so profoundly mysterious Dan about 3D-rendering? Any 2D image can be 3D rendered, provided there's some appreciable stepped gradations or (better still) smooth gradients of image intensity. The 3D-rendering programs such as ImageJ simply convert image intensity to apparent height above a base plane to create pseudo-3D. The settings one selects are entirely arbitrary and indeed subjective if one has never seen the template from which the 2D image was derived., as is the case with the Shroud of Turin, where all we have is the imprint, comparable to Fig.2 above, with no Fig.1

Image superficiality? (Sorry, no graphics).

See this link from my posting immediately preceding this one.

Rembrandt thickened paints with flour

It quotes the typical thickness of oil paint on old Rembrandts as being approximately one-thousandth of a mm, i.e. 1 micrometre, or 1000nm. Granted, that's greater then the 'guesstimated'  thickness of the TS image. (Not measured directly, I hasten to add, simply  assumed to be of the same order as the wavelength range of visible light, being based upon inability to "see" i.e. resolve the image in cross-section under the microscope). Now then, if  highly visible artist's paint with flour thickener can be as thin as 1000nm, it's not difficult to see how an image layer at the limit of visibility could be even thinner. What if the image layer were a faint  scorch, or, better still me(currently)thinks  Joseph Accetta's DYE imprinting  (now this blogger's preferred hypothesis in place of a previous fixation with thermal imprinting aka scorching.)   That's even supposing that the image today is  still that of the chosen dye bonding to linen. As suggested here previously, it's not impossible that what we see now is merely a 'ghost' image that survives after the dye has faded.  How might that happen?  One possibility is that alum (potassium aluminium sulphate) was used as a mordant to attach the dye to the linen. But alum is strongly acidic (it hydrolyses in water to form sulphuric acid). The latter could gradually cause faint but permanent discoloration of the most superficial part of linen fibres via chemical dehydration (a process that mimics scorching by heat) and those coloured caramelised products might survive long after the dye has faded.

Already there seem no good reasons for describing a 200-600nm image thickness as "enigmatic".  "Not beyond the realms of expectation"  would seem a more fitting less hyped-up description -  hardly the stuff of enigmas.

Conclusion so far: there is really nothing in the Shroud's image - at least at the macroscopic level - to justify describing it as "enigmatic". Its properties are entirely consistent with those of an imprint obtained from a 3D or bas relief template - namely a negative (with obligatory light/dark reversal), a mirror image (left/right reversal, due to a template being turned through 180 degrees towards linen, away from operator*), non-directional character (being an imprint, not a portrait relying  on light/shade to hint at form, i.e  "3D-ness", and probably superficial, given that a dye (or less probably a scorch) was used instead of paint to simulate the faint aged imprint (sweat?) that a deceased victim of crucifixion  might have left on linen many centuries earlier.

* Whilst inconvenient, one could deploy a rubber stamp in a manner that did not requiring turning it away from one, e.g. by pressing a sheet of translucent paper DOWN onto the ink-coated stamp face-side UP,  and then viewing the result through the thin thickness of paper,  with a sheet of glass as support. In that situation, the image, while still a negative of the original, would now be the "right way round". The negative and mirror images are entirely different phenomena arising for entirely different reasons.

Afterthought: coin imprints! There one has the template (coin) face up, with paper on top, so there's no mirror image reversal:

Negative imprint, but NOT a mirror image due to imprinting geometry.

 

As above, after tone-reversal.Now back to a positive image, the highest relief looking more light-reflective.

Yes, they can be 3D-enhanced needless to say. But it's PSEUDO-bas relief, guided by knowledge of coins.

Taking all these points into consideration, I repeat: there appears to be nothing in the least bit enigmatic about the Shroud image. It's exactly what one would expect of a contact imprint, as can be modelled, as above, with a rubber stamp, real or imaginary, as distinct from a painting or with coin-rubbing (manually assisted to ensure best contact between relief and surface). When was a rubber stamp imprint or coin-rubbing ever described as enigmatic?


Addendum: as stated here and elsewhere, this blogger now aligns himself with Joseph Accetta in  thinking that the TS image was probably dyed onto the linen, rather than heat-scorched. (I would not have rated dyeing per se very highly, but for the fact that dyeing onto linen is difficult without use of a mordant, that the most common mordant - alum - is highly acidic, and that sulphuric acid from slow alum hydrolysis may explain the faint ghost image we see today (so I've gone beyond Dr. Accetta  somewhat). So how does printed fabric respond to the conversions outlined above?

I've chosen a printed fabric that obviously has no 3D history, but which shows some stepped changes in image density.

Here we go:

Printed cotton from image files

As above, after light/dark reversal in ImageJ (yes , I should maybe have converted to B/W, but these images are prettier).

As above, after 3D enhancement in ImageJ.

It cannot be said too often: ImageJ can be used to give pseudo-3D rendering to images that have no 3D history, simply by converting image density to pseudo relief on an imaginary vertical (z) axis.  There is no mystique where 3D enhancement is concerned (and certainly no "encoding" of 3D information can be assumed in a 2D image, merely because it responds to 3D-rendering).

Yes. I have some alum on order, and yes, I shall be attempting to model a ghost image on linen offcuts using alum and water pastes in varying proportions, or even dry powder, followed by exposure to moist atmospheres. There's still everything to play for in 'experimental Shroudology.'

Further thoughts: the chief drawback with any wet ink or dye technology was the risk of seepage through to the reverse side and, as we all know, there's no reverse image, at least not one that is visible to the naked eye (digital enhancement, as per Fanti et al, has revealed a 'second face' but it's hard to know whether that is real or artefactual).

The game changer is the possibility that a mordant was used. ("mordre" - French verb, infinitive, to bite). Yes. anyone can quickly "dye" linen or cotton, but will the intense colour  still be there in a year or two, especially after laundering? Mordants give the dye a real "bite" on the cloth such that the coloration is essentially permanent. (Whether still visible after the passage of centuries is another matter).

Might we finally have a handle on the Shroud-imprinting technology by assuming Accetta is correct with his dyeing, but taking it a stage further? Suppose alum had been used  as a mordant, applied first to impregnate the linen. Then suppose the dye imprinting was done, so that the dye attached quickly to the surface mordant, so there was no appreciable reverse-side coloration. Suppose the dye gradually faded, but the mordant slowly released sulphuric acid on exposure to moist air, and that the concentrated H2SO4 produced as a result of subsequent evaporation  then proceeded chemically to dehydrate and discolor the surface fibres of the linen, such that, centuries later, what we see is primarily those "ghost" yellow fibres.  Might it be possible to model that process (see above)?  We shall see.

Reminder: This blogger, being impressed initially by the ability of contact scorching to reproduce many of the crucial Shroud properties (but annoyingly not alleged absence of fluorescence under uv)  had found  a rationale for scorching through the linking by Noel Currer- Briggs of the de Charnys of Lirey (Geoffroi and Jeanne née Vergy) genealogically to an alleged Templar uncle (Geoffroi de Charney) and thegruesome events of 1314 (slow death by roasting over hot coals). Some curious features on the Lirey Pilgrim's badge sustained that 'symbolic scorch' model.

Everything then changed with detailed descriptions from Ian Wilson and others of the recently discovered Machy mould for a second Lirey badge, with an additional motif that I (and perhaps I alone, c'est la vie) consider to represent the Veil of Veronica. Might that be a hint that the Shroud was to be seen, not as a scorch imprint, but a sweat imprint? If so, how might a medieval artisan set about simulating a sweat imprint? It might have used light dry scorching to simulate an ancient sweat imprint, but was more likely - one would have thought - to have used some kind of wet chemical treatment, if only dyeing, while still needing a template to account for negative imprinting etc. That's where my thinking began to dovetail with that of Joseph Accetta's, except I see an additional role for a sulphuric acid  'impurity' in producing a secondary faint but more permanent ghost image, one that in passing has a resonance with Luigi Garlaschelli's ideas (sulphuric acid-contaminated artist's red ochre).

Pomegranates have been used as a source of yellow dye for millennia (there's said to be a mention in the bible!).

Here are two fascinating images I've discovered through googling. They show the effect of dyeing with pomegranate extract, either used "as is", with no further additions, OR with a mordant. The latter? Alum of course!

Pomegranate dye, without mordant (left); with mordant,right.

See this article of the 'Folk Fibers' site.


Update: have today bought a real date stamp from my local branch of Poundland for the princely sum of ...  yes, £1 (oh what a lovely recession).

This scan of the imprint, followed by B/W reversal in ImageJ, followed by 3D enhancement. says it all.There was serial stamping from top to bottom without reloading with ink. Note the way that the 3D response falls off with image intensity.

Update: 13th March

The alum has arrived, express delivery (parcel postage 3 times the cost of the chemical!). Have  seen its mordanting action with my own eyes, tested using a home-made dye extract from pomegranate rind.

Have hit on a simple way (in principle, assuming no unforseen hitches) in discriminating between the dye and any H2SO4-induced "scorch" forming underneath the dye/mordant combination. One adds diluted sodium hypochlorite after treatment /storage that selectively bleaches the overlying dye, but not the underlying scorch. These are early days, and the odds against getting a result are slim if the "ghost" image is one that is age-related or depends on lots of other things coming together in the correct sequence. Nothing ventured, nothing gained.

Update:14th March

The new line of experimentation is underway.

The dye is a boiling water extract of pomegranate rinds (rich in tannins, gallates etc).Used on its own it gives linen a yellow-brown to orange colour (top left)  When used on alum-mordanted linen one gets a greyish-green colour (top right).

Most but not all the dye can be bleached out with hypochlorite solution.  Interestingly there's a faint brown remnant that tends to be more intense on the alum pre-treated side. It may or may not be relevant to the Turin Shroud, these being early days.

 Another result (today's):

 Top (inside yellow box): a wet imprint from a brass crucifix that has been painted with a syrup from boiled/semi-evaporated pomegranate rind extract almost to dryness, after (a) conversion to negative image and (b) 3D enhancement in ImageJ.

Bottom (inside blue box): the dry imprint obtained/reported many months ago  by pressing the same crucifix (heated) into linen. It was not my best scorch imprint (much of the face being invisible) but was chosen for a preliminary rough comparison between rival wet and dry imprinting technologies.).

See the banner at the top of my specialist Shroud blog for other scorch results obtained from the same crucifix template.

 

New result in the pipeline- might it be THE answer to the "enigma" of the Shroud?  

I shall keep it under wraps for now, there being some controls that need to be done. One should not count chickens I know, but if all goes well, the title to the next posting might well be this:

Is the Shroud of Turin a ghost image – the original dye imprint having been lost to expose a previously hidden - albeit faint -  dye-mordant underlay?

Update Sunday March 15th

I need a name to describe my new modelling of the Shroud image  (inspired by Joseph Accetta) using an alternative to his iron/oak gall ink. Mine uses alum-mordanted concentrated aqueous extract of pomegranate rind deployed  not as ink, this syrup being deployed as a kind of  natural sticky “paint”. However, let’s make one thing abundantly clear. The pomegranate extract was NOT used to paint a free hand image (this blogger does NOT subscribe to the Charles Freeman strand of thought that blithely ignores the Shroud's negative image). The home-made pomegranate paint was applied to a 3D template that was then pressed down into linen to leave a NEGATIVE imprint, with no brush strokes, no directionality of any kind, and which responded after a fashion to 3D-enhancement in ImageJ, as expected of any image, good bad or indifferent,  that displays pigment density differences.

Some images will follow later in the day, showing essential steps in the new technique, which is simply offered as a model system (as was my contact scorch modelling) to show how certain key Shroud image characteristics can/may be reproduced, at least in part, with no claim that the chemicals and/or procedures used were the actual ones (That we may never know, not unless a previously lost or concealed 'tell all' manuscript were to emerge from some dusty14th century archive).

Provisionally. let's call it the AMPS -imprinted model (AMPS = Alum-Mordanted Pomegranate Syrup).

Brief summary of the AMPS technique:

1. Prepare syrupy concentrate from boiled pomegranate rind.

2. Paint syrup onto template (am using same brass crucifix as used previously for scorch imprinting).

3. Imprint left by pomegranate syrup on linen, the latter having first been impregnated with alum mordant.

Here's the imprint after washing and drying to remove unbound syrup. It's turned grey-green! Well, I did say it was a model system. The mordant has certainly done its job.

It's a simple matter to turn that green image into a more authentic-looking sepia using oxidising agents. Hypochlorite ("bleach!") worked instantly - tested above the waistline. Hydrogen peroxide works slowly after a fashion (below waistline). Yes, the model system is I grant you  being tested to its limits.

Was the alum essential?

Left: before washing. Right:after washing. The top image is the pomegranate imprint, without alum-mordanting. The lower is a contact scorch from a previous experiment with the same crucifix.

In fact, the alum was not essential, at least not for surviving a single wash with warm tap water. In other words, my pomegranate extract is a powerful dye in its own right, without alum assistance (it having been chosen after an internet search for natural dyestuffs). However, one cannot be certain that the fabricators of the Shroud image had used a dye that was so effective without a mordant. Alternatively, it's interesting to know that the TS image could in principle have been made without use of alum, should it be found there is little or no detectable aluminium in the image areas - the latter being still a contentious point, as discussed previously in connection with the known limitations of STURP's x-ray fluorescence to detect elements of low (less than 17) atomic number.

It's all to easy to start with a model, and then acquire unexpected results that distract from the initial ideas. Here's a case in point. The idea of a 'ghost image' under a dye-mordant combination, generated by slow release of sulphuric acid from the mordant, is being lost sight of. Why? Because it was orignally intended that bleach could be used to decolorise dye-mordant, exposing a 'chemical scorch'. But the bleach has acted different from expected - it's converted the green mordant-dye combination to a very intense sepia image that cannot (surely?) be a ghost image, but an oxidation product that is highly coloured, not "bleached". 

This seems a good time to break off, and carefully review the results so far against initial assumptions and predictions.  

Back again: that result with the bleach looked wrong somehow, and indeed probably was: insufficient bleach added. Am now getting almost complete bleaching of the pomegranate syrup imprint, with or without alum, when excess bleach is dripped on and allowed to do its thing for a few minutes. That  means the show is back on the road.  Here's a rough outline of the protocol for further experimentation, aimed at testing the alum-derived H2SO4 model:

1.  Imprint with pomegranate syrup onto alum-impregnated cloth.  That would represent the Mark 1 Shroud image - big and bold, almost certainly with reverse-side action as well, even with viscosity-increasing additives as proposed by Joseph Accetta. But that doesn't matter greatly if it's the dispensable Mark 1 image.

2. One then has to model the effect of ageing, wear and tear on that Mark 1 image, which would result in the flaking off of much of the image, and to fading of the colour due to exposure to light and oxygen (while all the while the alum is releasing sulphuric acid into the linen out of sight underneath the dye imprint). How can it be modelled? That's the difficult and uncertain part, but exposure to light and oxygen at slightly elevated temperaure for days or weeks even, with or without water vapour, might be the way to go.

3. At some stage it will then be necessary to see what is under the remaining dye/mordant stain. The latter will be taken of with an excess of hypochlorite bleach, but the latter will (I maintain) NOT bleach any "scorch" produced by sulphuric acid if as I suspect it behaves like a heat scorch, and is chemically-dehydrated carbohydrate as per STURP summary. So what one looks for is a ghost Mark 2 scorch image, faint sepia in colour, stubbornly remaining after bleach treatment, probably (hopefully) with no reverse-side discoloration. It would also be interesting to check out any remaining Mark 2 scorch image under a uv lamp. If it behaves like the "etched-on" model images produced by Luigi Garlaschelli with his acidified metal oxide slurries, it too will be non-fluorescent, matching yet another of the (alleged) properties of the TS image.

Update: Monday March 16

Interestingly, there's a parallel chemical system to that of alum  with its Al2(SO4)3 as "active ingredient".  It's based on iron(III) sulphate, Fe2(SO4)3. The resemblance is close (both their solutions being strongly acidic, due to hydrolysis to sulphuric acid).

Indeed, it may be that everything that has been attributed so far to alum mordant producing sulphuric acid and a ghost image may in fact be due to an iron-based mordant action instead.  If that were the case it would allow one to make some inferences that could resolve the 'unfinished business' re Walter McCrone's focus on traces of 'too pure' iron oxide on the Shroud.

I shall now take a break while assembling an iron dossier. Be prepared for a further instalment in due course on what might loosely be termed the non-thermal scorch hypothesis, mediated by slow-acting sulphuric acid substituting for hot metal template as a chemical dehydrating agent,  and derived from hydrolysis of alum OR iron(III) sulphate.

Al2(SO4)3 + 6H2O  ->  2Al(OH)3 + 3H2SO4

or:

Fe2(SO4)3 + 6H2O ->  2Fe(OH)3 + 3H2SO4

Note: either of the two hydroxides can easily rearrange to make the hydrated oxides, like, er. McCrone's iron oxide, accommodated within a "painted image" scenario. (Did he ever consider dyeing, as distinct from painting?).

In fact, there may not really be "iron(III)hydroxide"  (Fe+++ 3OH-) as generally written.

It's more correctly written as a hydrated mixed oxide/hydroxide:   Fe+++ (O--) (OH-) .H2O.

See the wiki entry for that interestingly revisionist version!

Speaking of which - dyeing that is -  the so-called "dye-rot" that degrades some ancient printed textiles has been attributed to iron-based mordants, especially those that use iron sulphates, as distinct from iron chlorides (sulphuric acid being non-volatile, unlike hydrochloric). 

Note the current focus on dyeing,  with initially soluble pigments, as distinct from painting with insoluble ones. Hat tip again to Joseph Accetta, assuming the problem of reverse-side (aka obverse-side) action can be resolved. If it can't, this blogger may need to revert to instant thermal scorching. For now, it's sufficient to flag up that difficulty, pointing out that penetration of a Mark 1 dye stain to the opposite side would not matter if it had now completely disappeared.What matters is the hypothesized Mark 2 ghost image. It's not inconceivable that it would be restricted to the top surface only, i.e. to the most superficial parts of the linen fibres in contact with the Mark1 dye-mordant combination.

Update Tuesday March 17

Extracts from new pomegranate. The tray on left has boiled concentrated extract from rind and pith only (not seeds). The one on right with the greenish tinge has added alum (potassium aluminium sulphate).

The two extracts have been imprinted onto linen offcuts for long term storage. The aim is to see if ghost images appear due to chemical dehydration of superficial linen fibres, mediated perhaps by alum-derived sulphuric acid.

Concentrated syrups were made so as to produce a paint-like consistency without external aids.The 'paint' has been used to imprint from a bas relief template.  However, an order has been placed for gum arabic (viscous solution in water) so as to allow that option to be explored, although there is then an alternative target for the sulphuric acid that might reduce effects on the linen carbohydrates.

Update Wednesday 18th March

J. Accetta's dye-imprinting idea, or dare one say paradigm, and my response to it here, is currently the subject of a posting on Dan Porter's shroudstory site. I've responded to the splendid David Goulet, but decided to exit as soon as the ad hom tendency made its inevitable appearance.

Invoking Occam's razor (entities should not be multiplied unnecessarily) is always a cheap shot employed by those who cannot bother to get acquainted with new thinking, who wish to to preemptively dismiss not just the research but the researcher.

In fact there's scarcely any grounds for invoking  Occam's razor right now. The dye-imprinting idea is Accetta's, not mine. All I have done is to focus on a particular aspect of medieval dyeing - the recourse to mordants that release sulphuric acid - and to link that to STURP's 1981 Summary. There we were told that the image had the chemical and spectral characteristics of chemically-dehydrated carbohydrates, and sulphuric acid was indeed specifically mentioned as an agent capable of dehydrating. 

 Quote (STURP 1981) : The scientific consensus is that the image was produced by something which resulted in oxidation, dehydration and conjugation of the polysaccharide structure of the microfibrils of the linen itself. Such changes can be duplicated in the laboratory by certain chemical and physical processes. A similar type of change in linen can be obtained by sulfuric acid or heat. However, there are no chemical or physical methods known which can account for the totality of the image, nor can any combination of physical, chemical, biological or medical circumstances explain the image adequately.

All I have done is marry together the STURP 1981  Summary with STURP's Joseph Accetta (St.Louis 2014) to get what I consider a coherent narrative, and am now in the process of designing experiments to test the hypothesis. Suggestions that this blogger/retired science bod is an innocent abroad, 'multiplying entities unnecessarily', coming as they do from someone who acknowledges he hasn't read one's postings in full, are hardly calculated to impress, especially when there's so much work needing to be done, and all at my own expense needless to say.  Speaking of which: today I must place orders for iron sulphates. I shall play safe, and acquire both iron (II) aka ferrous sulphate and iron (III) aka ferric sulphate. Stocks of high quality linen also need replenishing.

Speaking of the shroudstory site, it was there that some of us had our first glimpse of what Joseph Accetta intended to say at the St.Louis conference in October the same year.

Here's a comment I attached to that posting. Note the singling out of sulphuric acid as (possibly) the crucial ingredient:

colinsberry

June 5, 2014 at 12:55 pm

Reply

Try downloading this PowerPoint presentation from Joseph Accetta, David (he being the subject of a recent posting here, and one of STURP’s genuinely scientific, non-agenda driven, non grandstanding participants in my view).

http://www.holyshroudguild.org/media/%20INFRARED%20IMAGING%20AND%20SPECTROSCOPIC%20PHENOMENOLOGY%20OF%20THE%20TURIN%20SHROUD.ppsx
(Unzip as if a pdf).

Go to the last few pages (approx 24/25). There you will see model spectroscopic (ir) studies not just with thermally-imprinted scorches, but also with linen that has been chemically dehydrated with 36% H2SO4 and even your invisible ink (lemon juice).

I’d be the first to admit there may be little to distinguish between an image produced by chemical as distinct from thermal dehydration (especially if chemical action was heat-assisted – see Luigi Garlaschelli’s model ‘frottage’ imprinting with acid-contaminated red iron oxide). It’s the vehicle for acid that is important (not too runny, not too viscous).
Some of us eagerly await details of what JA will say at St.Louis. Let’s hope it receives more attention than his meticulous and detailed studies to date.
Nuff said. I’m thinking of doing a post dedicated entirely to JA (he being my kind of scientist).

Update, still 18 March

David Goulet reminded me yesterday of an exchange we had in mid-January on  a shroudstory posting on Accetta's dye-imprinting. As can be seen, this blogger was making no secret of his scepticism as little as 2 months ago!

David Goulet

January 14, 2015 at 9:41 am

Reply

So the bas relief theory but using a woodprint? And the mechanism of image formation to the cloth?

Colin Berry

January 14, 2015 at 10:22 am

Reply

It’s a wet method that’s being proposed, David, based on ancient recipes for printing ink (iron gallate, gallic acid being trihydroxybenzoic acid, a natural plant-derived product). While simpler, less fiddly in practice than scorch-imprinting off a hot template, it’s going to be harder obviously to tick all the boxes re superficiality, lack of colour penetration etc.
If a woodprint had been used as template, would it not have been possible to get a more realistic differentiation, say between hair and skin?
My money’s still on thermal imprinting off a bas relief or 3D template(s.) Most of those who say it fails to match this or that feature of the TS have never done a scorch imprint in their lives, and/or don’t wish to know about the subtle effects that are achievable with relatively small changes in technology. Dry, e.g. thermal imprinting, maybe with chemically-sensitized linen, gives a far more predictable outcome. What’s more, it can chemically /permanently modify the most superficial fibres of the linen. It beats simply sticking something to them that can subsequently drop off (or be claimed without a shred of evidence to have done so, leaving, as if by magic, chemically modified fibres, ghost images still with 3D properties etc!).

David Goulet

January 14, 2015 at 10:33 am

Reply

Thanks for the summary, Colin. Agreed, the woodprint/wet theory has some major hurdles to overcome.