We need to know much more about the chemistry of linen pyrolysis before excluding the scorch hypothesis


Postscript (correction: ‘prescript‘) added July 2019:

You have arrived at a 2014 posting. That was the year in which this investigator finally abandoned the notion of the body image being made by direct scorch off a heated metal template (despite many attractions, like negative image, 3D response etc. But hear later: orchestral DA DA!  Yup, still there with the revised technology! DA DA! ).

In its place came two stage image production.

Stage 1: sprinkle white wheaten flour or suchlike vertically onto human subject from head to foot, front and rear  (ideally with initial smear of oil to act as weak adhesive). Shake off excess flour, then cover the lightly coated subject with wet linen. Press down VERTICALLY and firmly (thus avoiding sides of subject). Then (and here’s the key step):

Stage 2: suspend the linen horizontally over glowing charcoal embers and roast gently until the desired degree of coloration, thus ‘developing’ the flour imprint, so as to simulate a sweat-generated body image that has become yellowed with centuries of ageing.

The novel two-stage “flour-imprinting’ technology was unveiled initially on my generalist “sciencebuzz” site. (Warning: one has to search assiduously to find it, and it still uses a metal template, albeit unheated,  as distinct from human anatomy):


sbuzz oct 24, 14 flour 1


So it’s still thermal development of sorts, but with a key difference. One can take imprints off human anatomy (dead or alive!).

A final wash of the roasted flour imprint with soap and water yields a straw-coloured nebulous image, i.e. with fuzzy, poorly defined edges. It’s still a negative (tone-reversed) image that responds to 3D-rendering software, notably the splendid freely-downloadable ImageJ.  (Ring any bells? Better still, orchestral accompaniment – see , correction HEAR earlier – DA DA!))

This 2014 “prescript” replaces the one used for my earlier 2012/2013 postings, deploying abandoned ‘direct scorch’ technology.

Thank you for your patience and forbearance. Here’s where the original posting started:

Original posting starts here:



Mike M intro in blue

Mike M

February 9, 2014 at 6:17 pm | #44

Reply | Quote

Highly unlikely that someone would go to such details in an artwork (statue or painting), let alone demonstrate it in reverse. Who would appreciate these features in a negative image?…

I have seen plenty of crucifixes which show distorted rib cage and strained stomach muscles etc etc. Medieval sculptors went to considerable trouble to convey the trauma of crucifixion. If a life-size crucifix with these attributes had been heated and used to imprint a thermal image (“scorch”) then its surface relief would have been reproduced in the negative image on the linen, though perhaps not immediately apparent to viewers until Secondo Pia came along with his camera and plates in 1898 to convert negatives to positives.

 I hope someone of the scorch camp would be able to mention an example from the Middle Ages that rise to that exactitude.

Answered (see above)

 I have other reasons to doubt the scorch hypothesis. The lack of fluorescence in UV light(while scorches did) …

The presence or absence of fluorescence is difficult to discuss unless one knows precisely which molecules of pyrolysed linen are responsible (which we don’t)  and the temperature range and other conditions in which they are formed.

Using my latest “LOTTO” procedure, I find it quite difficult to scorch linen when the fabric is sandwiched between hot metal template and a DAMP cloth. It is possible that the presence of the latter affects not just the propensity to acquire a scorch, but propensity for that scorch to be fluorescent. Yes, that is pure speculation, but I would  maintain that fluorescence cannot be used as a diagnostic test for a heat scorch without doing a lot of validating  research first.

… image invisibility in transmitted light(while scorches did)

But the scorches being used for reference purposes are not necessarily reliable standards. They may have been formed under different conditions of temperature etc. Again, one needs a comprehensive knowledge of scorch characteristics, which we presently lack.

 … the mismatch of the colour of the lightly scorched fibres under the microscope with that of the image fibres(as demonstrated in Mario’s Shroudscope photomicroscope images).

Again, one is using the 1532 scorches as reference  material.  We have grounds for thinking they were not formed as described  (molten silver penetrating the reliquary and high air temperatures) but even if they were, what relevance would that be to a light contact scorch from brief contact with a heated template?

The lack of lumen discolouration in image fibres (unlike scorched fibres, as demonstrated by Rogers) .

The lumen is a space, so it’s not clear what Rogers meant by lumen (“medulla” was in fact his preferred term) discoloration. Maybe he meant the interface between lumen and fibre core, i.e. secondary cell wall, which would have been the remnants of the cytoplasm when the bast fibre was still a metabolically-active living cell . Given Rogers’ apparent weak grasp of botany (he definitely had a blind spot for the primary cell wall)  and the fact that he is sadly no longer here to take questions, it’s difficult to do justice to your point, except to point out that if, as I believe,  it’s the hemicelluloses that are most vulnerable to scorching, then one has to recall they are not exclusive to the PCW but are admixed with the core cellulose of the SCW as well (approc 15% of the latter).   Underneath a more or less intensely scorched PCW,  they may or may not discolour as far as the central lumen,  depending on conditions of temperature, contact time and pressure, presence of damp backing etc . Any comparisons one tries to make between image fibres and the Shroud’s own 1532 scorched fibres are bound to be fraught with uncertainties.

The impossibility of having a full body scorch without over-burning/under-burning fibres.

Have you seen my revised LOTTO procedure?  It does not produce over-burning or under-burning. Look at my site’s banner, and tell me where there is over-or under-burning.

 I also really enjoyed Thibault’s paper on scorching linen which demonstrated the fallacy of this claim.

I regret to say I didn’t,  not caring  for its  dogmatic and dismissive conclusions based on an unsatisfactory and dare I say UNFAIR model . In fact I produced a critique of Thibault’s findings, not reported Across The Way pointing out the unsuitability of his somewhat odd choice of template (failing to conform with most people’s idea of bas-relief, having just  two stepped planes, and not surprisingly giving excessive contrast between the images from the two planes, the characteristic that he essentially weaponised in order to dismiss the scorch hypothesis).

I considered his model was almost guaranteed to produce an  unflattering account of the scorch hypothesis, as did that of Paolo di Lazzaro when he used, correction, was invited to use Dan Porter’s site to report his own one-off customised UNFAIR coin experiment (with excessive temperature and/or contact time, similarly guaranteed to produce in that instance an excessive degree of scorching). He couldn’t even be bothered to respond to my comments.

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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2 Responses to We need to know much more about the chemistry of linen pyrolysis before excluding the scorch hypothesis

  1. The scorch Idea is wrong for the image, take a manikin head and dip ii in somthing that will transfer and place it in the head so that the same side of your cloth covers the back of the head as well as the face, then compare to the SOT and that will prove that is not how the image was made, then do the same thing with a hot head and compare and you will see that draping a cloth over a hot statue will not produce an image like the SOT

  2. colinsberry says:

    It’s late here, so I’ll just post a holding reply MutantB.

    I’m not clear why you refer to a wet dip system first, especially as you are apparently using it to image front and back simultaneously. That’s not the appropriate model for scorching, where two separate imprints are made, frontal then dorsal.
    As for your second point, I fail to see how you can be so categorical that scorching cannot work. Have you done any experiments yourself? I have, admittedly on a small-scale. Look at the banner on this page, showing the thermal imprint I obtained from a heated brass crucifix, and the way it responded to inversion and 3D enhancement in ImageJ. What’s not to like?

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