Is the Man on the Turin Shroud a pseudo-negative imprint from a DEATH MASK? (Could that be why the modern-day photographic negative looks so much better than the original?).

Look carefully at the sepia photograph on the left. There are two important things you need to know about it. Firstly, while it is a photographic positive, it might reasonably be described as a pseudo-negative. Why? Because of the position of the studio light, illuminating the subject from below and slightly to one side so that a feature like the nose, say, that normally appears light in a photograph is plunged into shade created by the subject’s chin etc, and now appears dark.

Now look at the picture on the right. It is a light/dark reversed negative, but because the original was a pseudo-negative, it in fact looks more like a positive.

Ring any bells?  Yes, the sepia image of the Man in the Turin Shroud has often been described as a pseudo-negative, ever since Secondo Pia in 1898 discovered the near-miraculous transformation achieved by converting to a real negative, and finding it too looks more like a positive (no doubt for the same reasons).

Some have seized on photographic terminology and jumped to a false conclusion –namely that the Shroud image is itself a photograph, suggesting there was a miraculous burst of energy in a 1st century tomb that somehow imprinted the image of a shroud-enclosed corpse onto the linen. Quite how that was achieved without a light-receptive ‘photographic’ emulsion, or converging lens,  chemical developers or the other paraphernalia of the photographic studio we are not told, and in any case that narrative does not square with the carbon dating (1260 to 1390). Another theory says that the Shroud image was made by Leonardo Da Vinci ( 1452-1519  ), perhaps using a camera obscura, but Renaissance Man came along too late to fit the C-dating.

In any case, it is the job of scientists like myself (albeit long retired) to develop testable ideas and theories that fit with the available evidence, and which do not require paranormal explanations much beloved of today’s enigmati. (Goodness knows what they are putting in the pizzas these days).

To show I mean business, I will now tell you something else about that image above that I have so far withheld, something  that may have contributed to the subjective enhancement achieved by converting the Shroud-like pseudo-negative to a real negative (and thus a pseudo-positive).

Some of you may have guessed already. The image is more Shroud-like than you may have imagined. It is that of Frederik Chopin ( 1810-1849). What’s more, the one on the left is his death mask. So if you were thinking it had a somewhat sepulchral quality to it, you were right. But can the same be said of the pseudo-positive?  It’s a matter for individual judgement, obviously, beauty, especially post-mortem beauty being in the eye of the beholder, but had I been shown the image on the right, I for one would not have immediately declared it to be that of a corpse. Asleep perhaps, possibly unconscious, or maybe just deep in thought, mentally composing one of his Nocturnes?

One thing leads to another. I long ago suggested that the image of the Man in the Shroud was obtained by thermal imprinting (“scorching”) from a template, fashioned perhaps in heat-resistant metal or ceramics.  I refined the idea by suggesting that the template was thrust into linen spread over a bed of sand or similar to get a good imprint, and that the template (uncharitably described by some wag as a “tin man”) was either a full 3D statue , say a bronze,  or maybe two separate front and back shallow bas-reliefs.

Well, you can probably guess what is coming, based on that image above, and the way that the pseudo-negative responds Shroud-like to being light/dark reversed. I now propose that the Shroud image was produced by medieval artisans who began with the body of a dead man, from which they obtained a death mask from the face, and then from the rest of the body, either in one go, or in separate sections later married up.

To get the death mask, the face was first smeared with oil, the hair especially, and then coated with plaster of Paris or something similar that sets solid. The mask was then carefully detached from the face (and body) and used as a mould for producing a bas-relief replica, e.g. by coating the inside with oil, and then filling with more wet plaster.

It is not only the face that can be captured for posterity in the form of a 3D cast.
Cast of Chopin’s left hand by Clésinger, the same compatriot of Chopin’s who produced the death mask.

On setting, the “positive” replica was removed from the mould, and then heated  and pressed into linen to produce a  faint and superficial scorch – the latter being a negative image of the original subject.  But the scorch was NOT a photographic image, note, but a thermal imprint, so it’s perhaps better to call it a pseudo-negative. If it is to be described as some kind of  x–graph, then it is a thermograph, or maybe a pyrograph (see Irene Corgiat’s use of an electric  pyrotool  – rather like a hot soldering iron – to produce a passable imitation of the man in the Shroud)..

SUDDEN THOUGHT: Maybe those prominent lines above the head and below the chin are NOT scorched-in crease marks as I have proposed earlier:  Why does the Turin Shroud appear to have scorched-in crease marks? Tell-tale signature for medieval forging?
Maybe the plaster template cracked in at least two places when being thrust into the linen, creating a small gap!

I believe this theory can explain a number of subtleties regarding the Shroud image. But for now, the point I would stress is that it accounts for the startling transformation that can be achieved in a single photographic step – converting an unattractive (and some might say somewhat grotesque) pseudo-negative into a more life-like image – and a serene and luminous one at that.

Even photographs that are not any kind of negative, pseudo- or otherwise, can benefit from being turned into real photographic negatives, contrary perhaps to one’s expectations. See some examples below.

In conclusion,the remarkable transformation of the Shroud image achieved first by Secondo Pia in 1898 is due to the coupled linking of three entirely artisan-like activities: first the production of a 3D replica of a real human being, albeit deceased, i.e. a death mask, secondly the production of a thermal imprint from the replica that was a pseudo-negative, and then finally the conversion of the pseudo-negative back to a positive image with photography. The latter, not surprisingly, contains encoded 3D information, revealed when image density is plotted as relief.  See my blog banner at the top of this and other postings, showing an experiment – my own – with a simple metal template that was used to make a pseudo-negative scorch mark. The latter  could be converted back to a positive, using simple light/dark reversal, and then displayed as a semi-3D image using ImageJ software to resemble closely the original trinket, with some of the  gentle, soft-focus but highly luminous quality of the iconic Shroud image after similar processing (top left of banner).

I’d say we were getting there, wouldn’t you?  Think death mask. Think thermal imprinting. Forget about corona discharges, forget about uv laser beams (some of you who may be reading this need to change your pizza supplier).

 Colin Berry, retired science bod, August 26th, 2012
Further reading:  here’s one I made earlier (March 16th):
How the Shroud’s mask-like face is explained away as irregularities in the linen – a prime example of misinformation and/or clutching at straws

Word of warning to would-be experimentalists, who might be toying with the idea of making a “life mask” as substitute for a death mask :

From wiki:

“The chemical reaction that occurs when plaster is mixed with water is exothermic in nature and can therefore cause severe burns. The potential dangers were demonstrated in January 2007, when a sixteen-year-old girl suffered third-degree burns after encasing her hands in a bucket of plaster as part of a school art project in Lincolnshire, England.

The burns were so severe that she subsequently had both thumbs and six of her fingers amputated.[5][6][7] For this reason only thin layers of plaster should be used, with time to cool between layers, or strips of cloth in plaster laid-up in the method used by the medical field. In place of plaster, alginate can safely be used for casting body parts.”

How to make a plaster death mask

Making a death mask.  (For how to cast a live face in plaster, using modern materials, see:






About Colin Berry

Retired science bod, previous research interests: phototherapy of neonatal jaundice, membrane influences on microsomal UDP-glucuronyltransferase, defective bilirubin and xenobiotic conjugation and hepatic excretion, dietary fibre and resistant starch.
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10 Responses to Is the Man on the Turin Shroud a pseudo-negative imprint from a DEATH MASK? (Could that be why the modern-day photographic negative looks so much better than the original?).

  1. Matthias says:

    Historic precedent for death masks in the 1200s/ 1300s?

  2. colinsberry says:

    Here’s a handy quotation that goes some of the way to addressing that point of yours. Matthias.

    “We find in France, then, as part of this elaborate cult of the dead the practice of forming a death mask of the deceased king. Nor did the death mask serve directly to hand down to posterity the features of a great man. The death mask is simply a technical aid in modelling the face of the effigies. It is this, the wax image of a living man, contrasting strangely with the mortal remains of the dead, which interests alike the artist and the public.

    But the death mask is a mere by-product in the concern of the survivors for the dead. It was not till the beginning of the fifteenth century that the grasp of reality was accepted as the aesthetic norm in the artistic production of Europe. It is therefore almost safe to assert that we shall not meet with the death mask before that period.

    In fact it is on the death of Charles VI. of France in 1422 that we first hear how Maitre Francois d’Orleans, court painter since 1408, made a death mask, as well as models of the hands and feet, from the corpse for the purpose of a magnificent image. Thus it is possible to prove by means of written records the use of the death mask in the preparations for the strange funeral ceremonies of all French kings of the Quattrocento, with the sole exception of Louis XI. (1461-83).”

    So there are two crucial points. Firstly, death masks did not really become acceptable until the “start of the 15th century”, which is some 50 years after the first reported exhibition of the Shroud in Lirey, and then for royalty only. But that was on account of a shift in cultural norms we are told, in which folk gradually became accustomed to the shock value of a replica taken from a deceased individual.

    So while it might appear at first sight that a Shroud image produced via a death mask replica was somewhat before its time, though not greatly, let’s not forget that it was not the 3D or semi-3D death mask per se that was on display, but simply a faint 2D sepia image that while recognizable as a man, and probably a deceased one, had little or none of the ghoulish quality of a 3D death mask.

    In fact, it is not that the technology did not exist prior to the 15th century. The technology for producing a death mask had been in existence for millennia, it being used by goldsmiths and bronze-makers etc, for example, to produce accurate replicas of things like plants, animals, people.

    Note that I am thinking of the Shroud having first been produced as a tribute to a Templar martyr, maybe a nuanced tribute but with no overt attempt to hoodwink. If on the other hand it had been a medieval forgery, i.e. intended to be accepted from the word go as Christ’s burial Shroud (which I think improbable in view of the understated Lirey badge) then I doubt that the forger would have been unduly bothered by the charge that he was exhibiting an anachronistic indifference to the cultural or artistic norms of his era … As I say, the death mask was probably just an intermediary stage… with few pilgrims so much as suspecting that it had played a key role…

  3. Matthias says:

    Thanks Colin.
    It still seems a rather odd tribute to me. Why not a painting, or a statue. Yes I know he was burnt at the stake, hence maybe giving someone the idea of scorching his image onto a cloth. I’m just finding it hard to reconcile what is a good theory of yours with the actual reason why it would be done.
    It really would be good if someone could do further research on the fluorescence issue. You couldn’t pursue this further?
    I think your theory really needs to be tested further. If lighter scorches don’t fluoresce then we can truly say your theory stacks up very favourably. If they do, then it might be time to move on from your scorch theory.
    Is there not a scientist’s arm you could pull? As I doubt pro-authenticists will be rushing to test this, as the current argument suits them just fine.

    • colinsberry says:

      Hmmm. Do I not detect some surreptitious moving of goalposts during the night? The customary challenge to us science bods is to come up with an explanation as to HOW it was done, not why it was done. The latter is best left methinks to psychologists, medieval psychologists to be more precise, assuming any exist.

      Nope, I’m not rising to the challenge on the fluorescence issue either. There one is up against the time-honoured human predilection to have one’s cake and eat it. I refer to the constant taunts that come my way that a scorch does not meet the criterion of superficiality (less than 200nm thick we are told). When I say that a scorch can be as superficial as one wishes, right down to the limits of detection by the human eye, back they come and say that my scorch HAS TO BE fluorescent, just like the (non-superficial) 1532 burn marks. Methinks they need to be consistent if they wish to be taken seriously. Constantly ducking and diving simply to score sparring points may help pass the time of day on internet forums, but it ain’t science – or even serious debate.

      Repeat: I say that the Shroud image is a highly-superficial scorch, far too superficial to show fluorescent properties. If there are those who dislike my position, then all they need do for starters is prove me wrong on the fluorescence. But the kind of people who have access to uv excimer lasers (naming no names!) can surely beg, borrow or steal a decent uv source, with variable wavelength control. Speaking for myself, I have no intention of embarking on half-baked experiments with £30 second hand equipment bought off eBay anytime soon…

  4. Matthias says:

    Well, Colin, that’s a bit disappointing for a Shroud agnostic like me. I am compelled by much of your theory, but the fluorescence is an outstanding question. I am not a scientist and have no connection to scientists. As I said, I do not expect the pro-authenticity crowd to test the theory, as an answer consistent with your theory would obviously undermine their case (conversely, of course, an answer hostile to your theory would do them great good!). You have an opportunity here to really underline the strength of your argument, and perhaps get close to putting the final nail in the coffin of the pro-authenticity crowd’s argument.
    I think the question of fluorescence is an important one – for me the answer would probably get me off the fence either to the pro or anti authenticity camp.
    Perhaps you could “name a name” in terms of someone who has access to a UV excimer laser. By your cryptic message I am assuming someone like Fanti who is a scientist within the pro-authenticity camp?
    Well, I might even email Fanti or someone of his ilk.

    • colinsberry says:

      I had the fluorescence argument thrown at me out of the blue by the President of STERA no less. (That for the uninitiated is the so-called “Shroud of Turin Education and Research Association”).

      Call me old-fashioned or a science snob if you like, but I don’t think it is the job of a photographer-cum-copyright hoarder to be dictating the scientific agenda, even if he does now delude himself into thinking that 30 years of association with the Shroud now makes him a scientist. If he were a scientist, he would not be bandying around the issue of fluorescence knowing and caring nothing about the origin of the phenomenon, and merely content to use it as an errant Scud missile to demolish my case for scorching. (You can find his comments on sidekick- Porter’s site – made back in February as I recall).

      There is no case to answer as far as I am concerned, since it is based on the false premise that if a 1532 burn mark that produced full thickness charring generates fluorochromes, notably benzenoid aromatics, then so should any thermal process that produced the Shroud image, no matter how superficial in comparison. If that is the view of Barrie Schwortz and others who deploy pseudo-science in defence of authenticity, then let THEM do the necessary experiments with graduated temperatures.

      For my part I refuse to be drawn into phoney arguments that have no scientific underpinning. The key question, as far as I am concerned, is the precise chemical nature of the tan-coloured chromophores, and whether they are modified linen carbohydrates per se or impurities. The priority is to initiate long-overdue model studies, starting initially with plain linen (without those Pliny additives that so fixated Raymond Rogers!) which is then progressively heated and pyrolysed, monitoring the changes using as wide a range of physical and chemical methods as possible, and (Shroud custodians willing) comparing with the image on the Shroud. If a match can be found that stands up to close scrutiny, with no quarter given to those who attempt to dismiss on trivial or pseudo-scientific grounds, then perhaps an answer can be found to the question: how could the Shroud image have been produced in medieval times, corresponding to the radiocarbon dating?

      I am now 99% confident that those experiments will produce an answer, with the rider that fluorescence will play a minor role if any in defining the precise conditions needed to produce the Shroud image.

      At the risk of repeating myself, the energy source will be verified as being thermal, more specifically heat conduction (NOT electromagnetic radiation of any kind) requiring DIRECT CONTACT (no air gap) with a hot object to be precise. The temperature will be just sufficient to produce a faint and superficial scorch on the crowns of the weave, possibly modifying cellulose fibrils, but more likely to involve selective pyrolysis of PCW-associated hemicelluloses (xyloglucans etc).

      Again, thank you for your interest Matthias. Would I be correct in thinking you are “Matt” with whom I have previously debated elsewhere?

  5. Matthias says:

    Fair enough.
    Here’s another question – why would the creators of the shroud image create an image that is so faint, indeed difficult to discern to the naked eye of a real life observer, when they could create a scorched image that is stronger, if they were indeed creating a memorial to a respected leader? That doesn’t sound credible to me. I know you are interested in the science more so that history and psychology, but credible theories on the shroud require both science AND history
    Again I’m not a scientist so would be interested in your answer as a science bod. Might the image have been stronger at first but then faded over time? Is that a credible possibility?
    Look forward to your reply

    • colinsberry says:

      Is there not some double think about the ease of visibility of the image on the Shroud? When one suggests that it is a scorch, one is told that the Shroud image is far too faint and superficial to be a mundane scorch. Yet when it comes to explaining the embarrassing gap in the Shroud’s history between the 1st and 14th century AD we are told that for part of that period at least it was on display as the Mandylion, albeit face only, inspiring and informing generations of artists as to the “real” appearance of Christ (beard, moustache, long hair etc). So the image was considered intense enough to warrant framing and displaying as the Mandylion, but not intense enough to have been produced by a resourceful manufacturer of made-to-order medieval icons. Yet another instance methinks of everlasting cake – the kind that can be saved yet devoured simultaneously.

      Seriously I have no insights into the question as to why things look the way they do, centuries after their first appearance. Certainly the initial image may have faded, due maybe to addition of active oxygen species (hydroxyl, hydroperoxy free radicals, singlet oxygen etc) across conjugated diene chromophores, resulting in less intense absorption of blue light, less yellow colour. (I have found that 6% w/v hydrogen peroxide solution can bleach the faintest scorches – but not the more intense ones). Alternatively, as some have suggested, as the the linen itself yellows with age, there is correspondingly less contrast between image and non-image areas.

      If as I believe the Shroud image was originally intended to convey graphically the idea of a hot corpse leaving its signature on linen (you may place whatever construction you wish on who was depicted, and the mechanism of imprinting) then the artist may well have aimed for a light as scorch as possible – while still visible from a few paces. Why? Because as I have suggested before, the crucial consideration may have been the need for ambiguity – because ambiguity generates an air of mystery. If the scorch is too intense, folk would simply dismiss it as a hot-metal brand. Make it too faint and they won’t see it. Make it sepia-coloured, and folk will ask themselves: am I seeing a faint scorch from heat? Or is it a faint STAIN from some kind of chemical interaction between a corpse and cloth.

      If ambiguity was deliberate, as I suspect, then it was spectacularly successful, given that radiation versus contact-scorching versus chemical Maillard reactions are still being discussed as alternatives to this day, some 660 years after the first recorded display in a remote French village in 1355. (Doesn’t say a great deal for STURP/STERA probing, does it?). One thing’s for certain. The image must have been intense enough to attract pilgrims in 1355, willing to part with money in order to take back home with them the Lirey Pilgrim’s badge… But the badge does NOT show the classical image of the crucified Christ, or even a typical Christ-like figure. What it does show is a matter of conjecture… I say it is that of a tortured Knight Templar, before or after slow-roasting, as was the ignominious fate of Jacques de Molay, Geoffroi de Charney and others whom we now describe as the last of the Knights Templar.

  6. Kateri says:

    Colinsberry, you forget the ‘Prays Manuscript’ Robert Du Clare mentions in his memoirs and the art depicting the Shroud of Turin as found in “the man of sorrows”, a compelling case for the Shroud of Turin being older then the dates specified by the Carbon 14th test. Then there is also medical forenstics of the blood flow on the arms and forehead which would be inconsistant with a body that was burned at the stake.

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