Shroud of Turin: performance characteristics of a simple uv lamp, chosen to check out claims that are dismissive of thermal imprinting mechanisms (Part 1 of 3).



OK, so the 1981 STURP summary did not describe the enigmatic image of the Man on the Turin Shroud as a “scorch”. The term “scorch” appeared nowhere, and this investigator no longer uses that term anyway, for reasons that will shortly be explained.

But the STURP summary came PDC to describing the image as having the characteristics of a scorch, as per the brown coloration one sees on linen when a hot iron on maximum setting (“linen”!) is held against it for too long. I quote (my bolding):

Furthermore, experiments in physics and chemistry with old linen have failed to reproduce adequately the phenomenon presented by the Shroud of Turin. 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.

Note the reference to “heat” (or acid) in the final sentence that is suggestive of a scorch mechanism, or at any rate “thermally-assisted” imprinting, such that the linen carbohydrates lose water molecules (“dehydration”), then undergoing further chemical change  (“oxidation”, “conjugation” ) that results in the tan or sepia coloration.

Sure, that seemingly specific reaction mechanism, based on re-arranging chemical structure with heat (or acid) as the input energy then gets clouded by what follows:

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.

Thus, the answer to the question of how the image was produced or what produced the image remains, now, as it has in the past, a mystery.

But it was a start, for this investigator at any rate, one who has explored both heat and acid as a means of imprinting tan-coloured images on linen (links can wait).  The first approach involved heating up bas relief templates (horse brasses etc) then pressing onto linen, and later still full 3D templates (e.g. brass crucifix) and obtaining what he regarded as promising results i.e. negative 3D-enhancible images, albeit with unanswered questions re superficiality still to be explored, both by me AND by sindonology generally, pending a breakthrough in image-probe techniques).

Direct scorch imprint (old technology!) onto linen from heated brass crucifix (left) to give negative image. Response to 3D rendering in ImageJ (centre). Combination of tone-reversal -to restore positive image- and 3D-rendering (right). So let's be hearing no more about the 'profoundly mysterious' negative ND 3D properties of the Man on TS. They are the expected properties of any contact imprint.

Old (Mark 1) direct scorch technology, now superceded by the two-stage Mark 2 flour imprinting technology (see banner).  It’s inserted here merely to show how well a scorch imprint responds to 3D enhancement, before and after performing a Secondo Pia style reversal of light v dark on the initial negative imprint. (Yes, it is imprinting rather than painting that explains why the TS body image is a negative, the latter not being exclusive to photography as so many seem to imagine).

Later, that model was superceded by the Mark 2 system, in which hot metal templates were abandoned. In their place was imprinting onto linen from real body anatomy (yipee, my own hand!) using  dry white flour onto dampened linen, and then roasting the imprinted linen in a hot oven to produce a sepia image (Mark 2 model). But Mark 1 and Mark 2 could both be described as thermal imprinting mechanisms, even if the term “scorch” model was appropriate for the first only.

But as soon as the Mark 1 model was proposed with its hot metal template, this investigator immediately attracted hostile targeted flak, from  Mr.Big of sindonology, a surviving STURP team member no less.  Here’s what he (STURP’s Documenting Photographer) said in a comment to the shroudstory site in Feb 2012 that now, nearly 4 years later, I shall shortly be able cautiously to respond to experimentally in three short postings, of which this one is the first.


Note the assumption that the scorch marks on the TS acquired in the 1532 fire are an appropriate benchmark for heat imprints generally, despite the precise conditions (temperature, oxygen, alleged contact with molten silver(?) etc being unknown. How scientific is that?

To business: here’s the uv lamp being put through its paces. The label on the box reads  “Mains Powered UV Bank Note Checker”, so that was the first test – to see if it showed up something on a bank note normally not visible.

UK banknote (£20) befoe and after switching on the uv lamp.

UK banknote (£20) before and after switching on the uv lamp.

Yes. It is fit for stated purpose – showing up the fluorescent security feature on a banknote.

Would it work with fluorescent marker pens?

Green felt tip marker pen, before and after uv illumination

Green felt tip marker pen, before and after uv illumination

Answer – yes. Spectacularly so.

And here’s a wider range of fluorescent marker pen inks, under the uv lamp.

Testing more fluorescent inks.

Testing more fluorescent inks.


Tonic water is famous for its blue fluorescence, sometimes visible in bright sunlight for those who like a G/T on the patio.  It’s due to the quinine that gives tonic its bitterness.  Here it is under the uv lamp:

Glass of tonic water under uv

Glass of tonic water under uv

Now for a more demanding test. Riboflavin, aka Vitamin B2, is well known for its yellow-green fluorescence. Was there a source in the house, without going out to buy vitamin pills? Possibly, given there’s some  Marmite in the house – “you either love it or loathe it” – (autolysed yeast extract), rich in B vitamins.



A little of the thick brown spread was dispersed in cold water to give a pale brown coloration, some of which was then spotted onto white tissue.

Testing marmite solution under the uv lamp

Testing marmite solution under the uv lamp. That’s the brown stuff in the middle with a faint yellow-green  halo under uv.

Problem: whilst one could see a faint green fluorescence under the uv lamp, especially when held close to the source of ‘black light’,  the fluorescence was scarcely visible in the photograph, appearing bluish-white rather than green. We had reached the operating limit of the uv lamp, designed  for less demanding tasks like detecting forged banknotes.

What about glass? Does it filter out uv, as frequently stated or assumed? I see no evidence for that, at least with the uv from the present source.

Ten microscope slides fail to block my uv light

Ten microscope slides fail to block my uv light

What about sunblock, aka sunscreen?

Sunblock smeared onto glass slide. Viewed first in ordinary visible light

Sunblock smeared onto glass slide, second slide then placed on top to make a thin sandwich.  Viewed first in ordinary visible light -scarcely visible.


Here’s the same after switching on the uv lamp (the latter right, out of picture):

As above ,illuminated with uv.

As above, illuminated with uv. Note the  way the sunblock does what it says on the label (except for thinner smear lower centre).

Let’s test the smeared slides as a rough-and-ready uv filter, given that glass alone does not work:

Uv filter brought alongside, but not fully in position

Uv filter/block brought alongside, but not fully in position


Sunblock works, by absorbing most of the incident uv rays, thus preventing fluorescence.

Sunblock works, by absorbing most of the incident uv rays, thus preventing fluorescence.

So what can I say, scientifically speaking, about the composition of the ultraviolet radiation from my recent  high-street purchase (major electrical retailer, Strand branch, London, UK). Answer: nothing. The unit came without a word of description on the box, apart from “Mains Powered UV Bank Note Checker, DETECTEUR  DE FAUX BILLETS,  UV Lamp shows Hidden Ultraviolet Features, Suitable for Most Currencies, Compact Design is Ideal for all Locations, Rugged Black Plastic Case, Mains Powered. Colour…Black; Power(W)…4; Dimensions(mm)…75x120x180;Weight (kg) …0.36

Brand name? None shown on the unit itself (it says EAGLE on the box, though that may be the importer/distributor, for which an address is given on Merseyside.

Country of origin? Nope, we’re not even told that, though one might make an educated guess.

There’s not even a booklet or so much as a leaflet inside the box, summarising technical details. What’s providing the uv radiation? It’s a cylindrical glass tube that glows violet. I suspect it contains mercury vapour, and provides mainly longwave ultraviolet, probably in the range 315nm – 400nm, aka UVA. But that’s a pure guess, maybe an educated one (I spent 2 years in the States in the early 70s irradiating bilirubin with intense white light with a strong blue component, but quickly dispensed with ordinary fluorescent tubes. Instead, I took the thick shield off of a high pressure mercury lamp designed to provide filtered uv, and simply had to accept that any results I obtained might have been due to the minor uv rather than major visible light component).

Is my lamp suitable for a scientific re-investigation of uv fluorescence, as it relates to the Turin Shroud, especially the STURP reports re the body image being non-fluorescent, compared with the 1532 burn holes that were?

Answer: No, definitely not. I am not here to posture as if still a working scientist (I’ve been retired since 2002).

So why am I writing this post, the first of three?

Answer: because  I now see my role more as a crime detective, looking for and sifting clues, seeking to ascertain who is  telling the unadorned truth, and who ain’t, and indeed is attempting to bullsh*t  with pseudoscience (and have already made significant progress seen in those brutally simple terms).

So don’t expect to see long technical screeds, table of numerical data etc etc. The most one can expect is to see my finger pointing in a certain direction, saying “that’s the way to go if you want my honest and candid opinion”.  Maybe you don’t, in which case you either aren’t reading this post, or,  if you are, may decide not to read the next two, based on findings with my high street bank note checker.


From the internet:

UVR (UV radiation) is divided into wavelength ranges identified as UVA (315 to 400 nm), UVB (280 to 315 nm), and UVC (100 to 280 nm). Of the solar UV energy reaching the equator, 95% is UVA and 5% is UVB

From this site: Sunscreens explained:

Sunscreens are products combining several ingredients that help prevent the sun’s ultraviolet (UV) radiation from reaching the skin. Two types of ultraviolet radiation,  UVA and UVB , damage the skin, age it prematurely, and increase your risk of skin cancer.

UVB is the chief culprit behind sunburn, while UVA rays, which penetrate the skin more deeply, are associated with wrinkling, leathering, sagging, and other light-induced effects of aging (photoaging ). They also exacerbate the carcinogenic effects of UVB rays, and increasingly are being seen as a cause of skin cancer on their own. Sunscreens vary in their ability to protect against UVA and UVB.

Posting 2 in this series will compare the effect of uv light from the new lamp on (a) Mark 1 contact scorches (hot metal template) with the margins of full-thickness burn holes in linen, the latter modelling the 1532 Chambery fire.

Posting 3 will look at the Mark 2 imprints obtained with white flour and a hot oven.

Time scale? Maybe a week, at most two.

Colin Berry

December 8, 2015.




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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