I shall start by being brutally frank regarding the attempt by Thibault Heimburger MD, a French physician, to dismiss the scorch hypothesis at one fell swoop.
The thrust of his paper is that there is little or no correspondence between his experimental scorch marks and the Shroud. His conclusion: the Shroud image is not a scorch.
Sorry, Thibault, but that conclusion is not justified, and neither is that how science is done, at least not the kind of approach to scientific research that I acquired in a training probably every bit as long as yours in medicine.
If one is going to make a comparison of the kind attempted, then the modelling of the scorching has to be relevant, and it has to be comprehensive. Yours is neither – as I have discussed in a preliminary posting on the macroscopic aspects – highlighting the failure to use a proper bas-relief template (see your own photograph above, to which I have added some lettering). A piece of metal with just two flat parallel planes is simply not fit for purpose. You yourself comment on the excessive contrast between the two scorched zones, yet seemed not to recognise that was method-dependent. Instead you attempt to devalue all the scorching that I and others have done (John Jackson included, whom you cite correctly as an authority) using more appropriate bas-relief templates that better model the gentler gradation of tone-contrasts and subtlety of the Shroud image. Because that’s what it’s all about – subtlety (at least you got that bit right).
Secondly, one does not make comparison with an artefact that all of us are agreed is at least 700 years old without considering the effects of ageing and other wear and tear. You make no mention of that, nor the various insults it has received. How about this lurid account from the shroud.com site (my bolding):
April 14, 1503 Good Friday: “… 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.’
I shall stop there for now, and post some detailed comments in the next few days as a series of instalments added on to the end of this posting. That will require addressing the criticial details that are in your photomicrographs, copyrighted ones included (STERA being prominently flagged up as per usual). If either you or the copyright owner (STERA = Barrie Schwortz Inc) has any objections to my reproducing and labelling those photographs, then do please let me know. I say that purely as a courtesy, given the use is for research purposes, falling within the “fair use” provisions.
Now for the detailed critique of the critique, so to speak:
OK, so the fibres are said to have a uniformly even yellow colour on the Shroud, whereas scorching, at least as performed by TH, produces a heterogeneous result, with a wider range of colours up to and including brown. But those are not grounds for rejecting scorching. Why not? Firstly, neither TH nor anyone else knows for certain what has caused the yellow colour. Is it not more witchcraft than science to go rejecting an idea based on a mere colour, uninformed, indeed totally ignorant as to the chemical nature of what one is dealing with. Secondly, TH has chosen particular experimental conditions to get his scorching, and the high contrast results that he considers so damning an indictment. I have previously criticized those conditions which he himself acknowledges resulted in excessive contrast (hardly surprising in view of the simplicity of his template that is sunk rather than bas relief). Is it not a little over-optimistic (to say the least) to imagine one has used the same template, the same operating conditions as a medieval forger? Underlay? Moist or dry? Temperature? Template material (metal? ceramic? plaster?). Linen ‘as is’, or coated, deliberately or accidentally with a thermosensitizer?
I say it is premature to reject a model simply because it does not reproduce the Shroud at first attempt especially when one is completely in the dark as to the nature of yellow chromophore. In any case the Shroud image is centuries old. Who is to say that it too did not have a heterogenous collection of fibres to begin with, and that the darker more brittle ones have not simply broken off, to leave the faintest ones that now look homogeneous?
Note the “tatty” appearance of the fibres that are within the blue circles, compared with other areas where they lie in neat undisturbed bundles with parallel fibres. Might these be regions in which the fibres were originally more heavily scorched, but being extra fragile, i.e. brittle, have gradually broken off with age and handling? Might this be the explanation for the rather uniform colour intensity of the fibres – there has been a process of attrition over the centuries, with a survival of the fittest fibres, i.e. those that were least scorched.
Second instalment: that arguably biased Introduction, with its references to fluorescence, not studied in this paper, and thus of highly questionable relevance and indeed objectivity. The author’s words are in italics, mine in standard font.
“One of the most important arguments against the scorch is related to UV fluorescence. It is well known that the UV/Vis fluorescence photography of the TS shows that the body image does not while the light scorches emit a reddish fluorescence. Miller and Pellicori performed several experiments using the same equipment as in Turin. They concluded: “The scorches associated with the fire of 1532 (…) attest to the rapid combustion of the available oxygen”. Check against French. Combustion or consumption?”
Do they mean “consumption” of the available oxygen? Maybe they are saying that scorching and charring, as distinct from being burned to ash, is suggestive of pyrolysis as distinct from combustion (in a different but related context, it is the difference between wood being converted to charcoal by heat in the absence of oxygen and wood burning with a flame and maybe later glowing red hot as charcoal oxidises finally to leave nothing but ash, i.e. complete combustion).
So for: “The scorches associated with the fire of 1532 (…) attest to the rapid combustion of the available oxygen” read: “…the conditions of the 1532 fire (inside a closed reliquary) favoured limited oxygen and thus pyrolysis or partial combustion rather than complete combustion.”
What they do not say, at this point, but was presumably the intended meaning, is that the red fluorescence of the 1532 scorches was due to pyrolysis in the presence of negligible amounts of oxygen, most having been quickly consumed in the raging fire outwith the reliquary.
“Their reddish emission is probably due to furfurals, which can be produced under such conditions”.
Possibly. Furan is a heterocyclic aldehyde (heterocyclic because the ring contains an oxygen atom rather than comprising carbon atoms only.) I need to look up its fluorescence characteristics. I have suggested elsewhere that the formation of aromatic compounds may be the reason for at least some fluorescence. There I was thinking primarily of benzenoid ring systems (all carbon, no oxygen). Furan? Benzenoids? There are many possibilities, each giving compounds with their own fluorescence characteristics. On top of this one has the likely complication of fluorescence quenching (even atmospheric oxygen can be a potent fluorescence quencher), which makes fluorescence a complex area, and hardly suited to ruling out (or ruling in) one or other theory as to how a particular scorch came to be formed, least of all one that was acquired many centuries ago.
“These conditions are obviously not the same as those expected for a medieval forger.”
No, obviously not.
“For that reason, the authors made several experiments in open air followed by ageing by baking the samples at 145°C. for 6 hours.”
Oh dear. There is an assumption that a forger’s scorch could not possibly be anaerobic, so conditions have been chosen to get maximum exposure to oxygen.
Faulty reasoning. Maybe the writer had not thought enough about the physics and chemistry of applying a hot metal template to linen. The first thing that happens is the heating of air in the pores of the linen that makes it expand. It then exits via pores of cloth to the outside, Already the region under the template is oxygen-deficient. Then the water associated with the linen is driven out as steam – superheated steam. The area is probably oxygen-free now for all intents and purposes. Then pyrolysis begins – more steam, and if the temperature is high enough, more volatiles of one description or another.
The attempt to drive a wedge between the 1532 scorch and the supposed medieval methods was presumably to explain why one fluoresces and the other does not. But the reasoning is fallacious, or at any rate conjectural unless one KNOWS for certain the precise conditions under which each occurred.
“They wrote: “linen lightly scorched by a soldering iron in air shows the green-yellow emission, often distributed in plumes of deposited pyrolysis products.”
No difficulty with that. Hugh Farey (see recent Comments on this site) confirmed this yellow-green fluorescence recently.
“We demonstrated in one experiment that the material of the plumes could be transported by water, but the underlying scorched cellulose retained a bright yellow-green fluorescence. (ed: objectivity alert* , since we are still in the Introduction): This demonstration together with the observed absence of body image fluorescence is strong evidence against the cause for the body image being a scorch”. (ed: my bolding”)
OK, so the Shroud (apparently) does not fluoresce at all, apart from the 1532 and other scorch marks from the “poker hole” and 1532 episodes. But it is premature to ascribe the differences to aerobic v anaerobic when so many factors can be operating. To attempt to dismiss scorching as mechanism on grounds that fluorescence should be present, not knowing the complete history of the Shroud, is not science. It could better be described as witchcraft.
“Although we do not know exactly what “lightly scorched linen” means, this demonstration still remains important.”
No, the demonstration is not important. One can try to make it seem important, but I repeat, it is not important. It is but one piece in a jigsaw that is no more or less “important” than many scores of other background pieces. (you know, like those difficult bits of sky or sea in a real jigsaw).
One has to prioritise on the the evidence. The fact that the Shroud image is highly superficial, scorch-like in appearance and IMPORTANTLY confined largely to the crowns of the threads (indeed, crowns are invariably scorched where one sees image) is the key consideration that says that the scorch hypothesis should under no circumstances be lightly dismissed, whether as here on on fluorescence or any other “witchcraft” grounds, unless one has a credible alternative hypothesis to account for the superficiality.
*I always pay special attention to Introductions. Not only do they often provide a clue as to the reasons why a particular project was chosen. They also give early warning signs, as here I regret to say, of a departure from strict scientific objectivity. In discussing fluorescence in the Introduction, TH was trying to undermine scorching before describing his own findings, without contributing to the fluorescence issue, something which in everyday life one might be minded to describe as a “softening up exercise”. Had I been asked to referee his paper (I used to referee papers for the Biochemical Journal and several others besides) I would have recommended that the fluorescence section be taken out of the Introduction and moved to Discussion.
In short, TH did no set out to TEST the scorch hypothesis. He set out to BURY IT, and with indecent haste (since rumours of its death, circulating for some 30 or more years, are somewhat exaggerated). TH thinks he’s being scientific, with his lists and tables of observations . But he falls at the first hurdle – his lack of objectivity is plain for all to see – even in the Introduction.
Sorry, TH, I’ve no doubt you are a fine physician, but the testing or falsification of scientific hypotheses is not the same as medical diagnosis. They may bear superficial resemblances, but I repeat: the two are not the same. It’s all about those known unknowns, and those unknown unknowns. I’ll leave you to figure that one out for yourself…
The next instalment will address the issue of superficial coloration of ‘crown’ threads and whether or not coloration that extends into the interstices precludes scorching by contact.
Change of plan (Tue 30 Oct): this posting has become unwieldy, so I am continuing this critique as a new more informal one (Part 3).