I'm all ready and rarin' to go with my dastardly new approach to modelling the Shroud, one that depends on imprinting a negative image onto linen from a template (or person?) coated in organic matter (to simulate bodily sweat), not forgetting those blood stains either in all the biblically-correct places. Then follows the crucial step: exposure to a mix of nitric acid and NOx fumes (see posting that preceded this one for the chemical whys and wherefores).
Here's my miniaturized set up for doing the experiment in the garage, with a crude but hopefully effective system of containing the fumes.
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| Set up for fumigating imprinted linen with vapour phase HNO3/NOx fumes |
The conc. nitric acid will placed in the broad-necked bottle - a cm so of depth should do. I may or may not add a few copper turnings to augment the supply of NOx (some forms naturally as a result of HNO3 photodissociation). The imprinted linen will then be suspended in the air space, using the ground glass stopper to hold it in place. Imprinting procedure? I'll paint that brass crucifix with some stiff protein gel for starters (that's powdered gelatin in the green/red sachet), and press down onto the linen to get the negative "body" imprint. (Note that a real body could be used in any scaled-up version, similar to Luigi Garlaschelli's memorable modelling via 'powder frottage' (though he too tested a slurry).
The sealed reaction vessel will then be placed in a gripseal poly bag, at the bottom of which will be some slaked lime or sodium bicarbonate (shown) to sequester any escaped acid fumes. Naturally I'll be wearing a makeshift face mask and goggles, though I survived decades in chemical, biochemical and medical laboratories without them (but they had fume- and spill containment facilities that my home garage lacks). Wish me luck, all those of you who share my curiosity as to how the Shroud was REALLY made (who may or may not buy into one or more the naturalistic or supernatural pro-authenticity scenarios that so dominate the world of "sindonology" and its attendant media circus).
I may tack some more on later, if the HNO3 fails to arrive today, like the numerous boxes that my fumigation model ticks (which doesn't make the hypothesis compelling - merely plausible - but as I've said before, that's the prime raison d'etre of the scientist in my view - to generate hypotheses that are plausible, and then turn them into working models for TESTING.
Late addition (11 April): for the attention of Adrie van der Hoeven
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| Nitrated cellulose can "leak"nitrogen slowly or explosively |
Sunday 12 April (still waiting for nitric acid to arrive)
Checklist of reasons (work in progress) for thinking there may be some mileage in the nitric acid fumigation model.
(Having
flagged up the possibility that some chemical changes might be due to
oxides of nitrogen, NOx, instead of or in addition to HNO3, I'll refer
now simply to the HNO3 model.).
1. If as I now
suspect, the TS was an attempt to simulate a sweat and blood imprint
onto "Joseph of Arimathea's linen", the latter receiving the traumatised
and bloodied body of Jesus straight from the cross, then a chemical
approach would have been the obvious way a forger/hoaxer would proceed.
2.
There was already a model of sorts for an image captured as a
consequence of facial imprinting, namely the legendary Veil of Veronica,
described by Neil MacGregor, until recently Director of the British
Museum, as Rome's central icon in the mid 14th century. The presence of
the vignette of a Jesus-like face above the word SVAIRE (Latin for face
cloth) added to the Machy mould for a Lirey pilgrims' badge variant
suggests that an attempt was being made to promote a whole body version
of the Veil, arriving a little later than the Veil, immediately post-crucifixion.
3.
How to simulate ancient sweat (1300 years old in the mid 14th century)?
It would need to look yellowed, rather faint, and, most important of
all, would need not be imprinted (not painted). In other words the final
image would not be like a painting, but what today we would call a
tone-reversed photographic negative. Secondo Pia's remarkable tone
inversion, 1898, is thus explained.
4.
One could use dye imprinting to produce that negative imprint, maybe
using a corpse as template or even a life-size bas relief woodcut as
suggested by Joe Accetta. However, might there be a less messy way of
genberating an image that used a non-pigmented substance for the initial
imprinting (allowing a living person to serve as template) and then
expose that primary image to a chemical treatment that coloured up the
imprint, leaving the background minimally altered. This kind of binary
system allows for better control and fine-tuning of the end-result. One can take one's time with the initial imprinting, even doing in stages if desired, eg, head separate from torso. One can also seek to produce a final 'chemograph' by using the chemistry follow-up as a photographer used weak developing solutions, exposing for seconds, minutes even until the required effect was obtained, then adding a neutralising agent to stop the process in its tracks.
5. Neutralising agent? Like a base or alkali that is used to nautralise an acid? Might the developing agent have been an acid? The newly-discovered strong mineral acids, which today we call sulphuric (H2SO4) hydrochloric (HCl) and nitric acid (HNO3) were all the rage in alchemical circles in 13th century Europe onwards (the Islamic world probably knew about them sooner, but the first clear recipe appeared under the (probable) pseudonym Geber, aka pseudo-Geber, thought by some to be the obscure Franciscan monk known only as Paul of Taranto). Might the new proto-chemistry and associated technology have provided a novel means of simulating the supersize-suaire? Might our Paul of Taranto have been the 'brains' behind it all, whether or not directly involved in the actual hands-on fabrication?
6. STURP described the TS image as that expected of chemically-modified linen carbohydrate, citing as reaction mechanism: chemical dehydration, oxidation, and formation of conjugated double-bonds (the latter comprising the yellow-brown chromophores). Those changes it said could arise from thermal effects ("scorching") or, alternatively, from certain acids, notably sulphuric. Others too have speculated on a role for sulphuric acid, notably Joe Accetta, Joe Nickell and Luigi Garlaschelli.
I tested sulphuric acid and found it wanting: linen tends to disintegrate when intermediate concentration (battery) strength sulphuric acid is allowed to evaporate and concentrate on linen before there is appreciable browning. Hydrochloric acid, being non-oxidizing, is not considered as good a candidate for creating an artificial sweat stain as NITRIC ACID, which is a powerful oxidizing agent. Moreover, it is generally contaminated with the chemically reactive oxides of nitrogen, collectively known as NOx. What's more the latter are formed when nitric acid oxidizes organic matter, so can arise as secondary products that add to the possible spectrum of reaction products.
The alchemist known as Pseudo-Geber described in the 13th century the generation of nitric acid fumes from strongly heating a mixture of Cyprus vitriol (cpper sulphate), saltpetre (potassium nitrate) and alum (potassium aluminium sulphate). The fumes could be condensed in a water-cooled collection vessel to fairly concentrated nitric acid with variable water and NOx content. Thus was made something that approximated to our modern day nitric acid. An alchemist who spiltit on his skin would have observed an immediate strong yellow colour. It is not an acid "burn" as such, but a reaction between nitric acid and the aromatic amino acid side chains of proteins, giving the so-called xanthoproteic reaction, the basis of the quick laboratory protein-test. Might that colour change have provided the germ of an idea for simulating a sweat imprint on linen? Might limited exposure to nitric acid fumes also endow linen with an 'aged' look, over and above the ability to turn protein stains yellow?
Provisional model: one paints one's human volunteer or corpse with a viscous dispersion of starch, or white flour, or gum arabic, or milk, egg white etc - in other words an imprinting medium that is carbohydrate and/or protein. The more gel-like the medium the better. One then covers with a sheet of linen and manually presses the fabric into and around the relief contours. The linen is then carefully pulled back, with its moist imprint, and then, with or without a drying step, is suspended in nitric acid fumes. It is withdrawn as soon as a distinct image of the subject appears against a lighter background. The image is due to oxidized carbohydrate, possibly with a contribution from nitrated protein. One does not leave in the acid for longer than is absolutely necessary for obvious reasons. After removal the imprinted linen is dusted with powdered chalk or some other agent that neutralizes acid.
7. Fumigation might help account for the otherwise mysterious side strip. (The continuity of weave across the seam joining two sections suggesting that the strip was cut off, then ra-attached later). Might the side strip have been part of a strategy to ensure even coloration with no telltale evidence of temporary supports like poles. pegs etc.
8. Fumigation might account for image superficiality - if one assumes that limited contact to fumes affects the most superficial layer and components of the linen fibre, namely the primary cell wall (PCW) and its relatively open network of polysaccharides (the chemically-reactive hemicelluloses being well represented).
9. The blood first/iamge second chronology is explainable as follows: the subject serving as template was first coated with imprint medium (as above). Bloodstains were then added in all the biblically correct places. Then the combined image was imprinted, such that blood imprinted onto the linen first, residing underneath the imprinting medium.
10. The present appearance of the blood on the TS, looking too red for old blood, and being described as by Adler and Heller as "acid methemoglobin" is explained by by supposing that nitric acid and/or NOx had two effects: first, to oxidise the iron to the ferric state (Fe+3) and then to attach some kind of nitrogenous species to the iron as ligand (NOx?) A possible resemblance to the curing of ham and bacon using nitrites (NO2-, see Appendix below) to make pink colours, as proposed earlier by this blogger, albeit in a somewhat different scenario (medicinal leech-stored human blood!) could serve as model, while noting Adrie van der Hoeven's inability to find closely matching spectral features. This one-time bilirubin specialist (mechanism of phototherapy for neonatal jaundice) has previously voiced strong opposition to Adler's poorly documented proposals for implicating "trauma of crucifixion" bilirubin in the permanent red colour of TS bloodstains (bilirubin being notoriously unstable to light and oxygen as Adler himself later acknowledged in his recommendations for Shroud conservation) .
5. Neutralising agent? Like a base or alkali that is used to nautralise an acid? Might the developing agent have been an acid? The newly-discovered strong mineral acids, which today we call sulphuric (H2SO4) hydrochloric (HCl) and nitric acid (HNO3) were all the rage in alchemical circles in 13th century Europe onwards (the Islamic world probably knew about them sooner, but the first clear recipe appeared under the (probable) pseudonym Geber, aka pseudo-Geber, thought by some to be the obscure Franciscan monk known only as Paul of Taranto). Might the new proto-chemistry and associated technology have provided a novel means of simulating the supersize-suaire? Might our Paul of Taranto have been the 'brains' behind it all, whether or not directly involved in the actual hands-on fabrication?
6. STURP described the TS image as that expected of chemically-modified linen carbohydrate, citing as reaction mechanism: chemical dehydration, oxidation, and formation of conjugated double-bonds (the latter comprising the yellow-brown chromophores). Those changes it said could arise from thermal effects ("scorching") or, alternatively, from certain acids, notably sulphuric. Others too have speculated on a role for sulphuric acid, notably Joe Accetta, Joe Nickell and Luigi Garlaschelli.
I tested sulphuric acid and found it wanting: linen tends to disintegrate when intermediate concentration (battery) strength sulphuric acid is allowed to evaporate and concentrate on linen before there is appreciable browning. Hydrochloric acid, being non-oxidizing, is not considered as good a candidate for creating an artificial sweat stain as NITRIC ACID, which is a powerful oxidizing agent. Moreover, it is generally contaminated with the chemically reactive oxides of nitrogen, collectively known as NOx. What's more the latter are formed when nitric acid oxidizes organic matter, so can arise as secondary products that add to the possible spectrum of reaction products.
The alchemist known as Pseudo-Geber described in the 13th century the generation of nitric acid fumes from strongly heating a mixture of Cyprus vitriol (cpper sulphate), saltpetre (potassium nitrate) and alum (potassium aluminium sulphate). The fumes could be condensed in a water-cooled collection vessel to fairly concentrated nitric acid with variable water and NOx content. Thus was made something that approximated to our modern day nitric acid. An alchemist who spiltit on his skin would have observed an immediate strong yellow colour. It is not an acid "burn" as such, but a reaction between nitric acid and the aromatic amino acid side chains of proteins, giving the so-called xanthoproteic reaction, the basis of the quick laboratory protein-test. Might that colour change have provided the germ of an idea for simulating a sweat imprint on linen? Might limited exposure to nitric acid fumes also endow linen with an 'aged' look, over and above the ability to turn protein stains yellow?
Provisional model: one paints one's human volunteer or corpse with a viscous dispersion of starch, or white flour, or gum arabic, or milk, egg white etc - in other words an imprinting medium that is carbohydrate and/or protein. The more gel-like the medium the better. One then covers with a sheet of linen and manually presses the fabric into and around the relief contours. The linen is then carefully pulled back, with its moist imprint, and then, with or without a drying step, is suspended in nitric acid fumes. It is withdrawn as soon as a distinct image of the subject appears against a lighter background. The image is due to oxidized carbohydrate, possibly with a contribution from nitrated protein. One does not leave in the acid for longer than is absolutely necessary for obvious reasons. After removal the imprinted linen is dusted with powdered chalk or some other agent that neutralizes acid.
7. Fumigation might help account for the otherwise mysterious side strip. (The continuity of weave across the seam joining two sections suggesting that the strip was cut off, then ra-attached later). Might the side strip have been part of a strategy to ensure even coloration with no telltale evidence of temporary supports like poles. pegs etc.
8. Fumigation might account for image superficiality - if one assumes that limited contact to fumes affects the most superficial layer and components of the linen fibre, namely the primary cell wall (PCW) and its relatively open network of polysaccharides (the chemically-reactive hemicelluloses being well represented).
9. The blood first/iamge second chronology is explainable as follows: the subject serving as template was first coated with imprint medium (as above). Bloodstains were then added in all the biblically correct places. Then the combined image was imprinted, such that blood imprinted onto the linen first, residing underneath the imprinting medium.
10. The present appearance of the blood on the TS, looking too red for old blood, and being described as by Adler and Heller as "acid methemoglobin" is explained by by supposing that nitric acid and/or NOx had two effects: first, to oxidise the iron to the ferric state (Fe+3) and then to attach some kind of nitrogenous species to the iron as ligand (NOx?) A possible resemblance to the curing of ham and bacon using nitrites (NO2-, see Appendix below) to make pink colours, as proposed earlier by this blogger, albeit in a somewhat different scenario (medicinal leech-stored human blood!) could serve as model, while noting Adrie van der Hoeven's inability to find closely matching spectral features. This one-time bilirubin specialist (mechanism of phototherapy for neonatal jaundice) has previously voiced strong opposition to Adler's poorly documented proposals for implicating "trauma of crucifixion" bilirubin in the permanent red colour of TS bloodstains (bilirubin being notoriously unstable to light and oxygen as Adler himself later acknowledged in his recommendations for Shroud conservation) .
11. Deterioration of a strong primary image to a fainter 'ghost' image is catered for, if one supposes that most or all of the imprinting medium flakes off over time, to leave an underlying remnant that is more intense than non-image background.
12. Fluorescence under uv? The Shroud body image is famously non-fluoresent, as I was repeatedly reminded when using hot metal "scorching" as a model. (I was not unduly perturbed, given that fluorescence means nothing centuries after the event: the fluorescent chromophores could have evaporated, oxidized, polymerized etc). However, an entirely different mechanism - chemical oxidation or even nitration by HNO3 fumes and accompanying NOx paints an entirely different picture, no pun intended.The products could be subtly different from those produced by thermal scorching. Alternatively, the presence of accompanying hydrogen ions /protons from the acid could quench fluorescence.
Monday April 13
Sent this shirty email yesterday to Malcomxxxx, the name that Amazon gave for the retailer supplying the nitric acid ( I placed my order 10 days ago, and pre-paid!)
Update 13 April
Adrie van der Hoeven (comments) has suggested that Fanti's corona discharge hypothesis might account for the TS image. Here's a couple of images that says it cannot and did not (think hair) :
12. Fluorescence under uv? The Shroud body image is famously non-fluoresent, as I was repeatedly reminded when using hot metal "scorching" as a model. (I was not unduly perturbed, given that fluorescence means nothing centuries after the event: the fluorescent chromophores could have evaporated, oxidized, polymerized etc). However, an entirely different mechanism - chemical oxidation or even nitration by HNO3 fumes and accompanying NOx paints an entirely different picture, no pun intended.The products could be subtly different from those produced by thermal scorching. Alternatively, the presence of accompanying hydrogen ions /protons from the acid could quench fluorescence.
Monday April 13
Sent this shirty email yesterday to Malcomxxxx, the name that Amazon gave for the retailer supplying the nitric acid ( I placed my order 10 days ago, and pre-paid!)
Previously when I've ordered through Amazon, Malcolm,
the goods have arrived on the start date for delivery.
So I was most disappointed that my nitric acid did not
arrive last Friday or yesterday, and now wonder if
I may have to wait as long as the last date
(Wed 22nd! for delivery). Sorry - not good enough,
not when one is paying over £6 for delivery.
I had expected better of an Amazon retailer. People who read my latest blog posting know I'm
waiting for nitric acid to test an important new idea
re the Turin Shroud. http://colinb-sciencebuzz.blogspot.co.uk/ Kind regardsColin Berry
Update 13 April
Adrie van der Hoeven (comments) has suggested that Fanti's corona discharge hypothesis might account for the TS image. Here's a couple of images that says it cannot and did not (think hair) :
See comment number 25 addressed to Adrie re Fanti's corona discharge theory.
Update: Tuesday 14 April
Have just stumbled upon this 1836 report on what nitric acid does to wheat flour versus wheat starch.
It states that: "Nitric acid has the property of coloring wheat flour of a fine orange-yellow whereas it neither affects the color of fecula nor starch".
Interesting, very interesting. Yesterday I made a syrupy dispersion of wheat flour in hot water, using it to 'paint' my brass crucifix, and then imprint a near-invisible image onto linen.
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| Ready to paint crucifix with wheat flour dispersion in hot water, prior to imprinting the wet image onto linen. |
When the nitric acid arrives (!) the linen will be suspended in the fumes. It would be most heartening if the nitric acid were to selectively colour, say, the proteins of the flour and the reactive hemicelluloses of the linen PCW, while leaving starch and cellulose relatively uncoloured.* Might one see a yellow TS-like image against a faint yellow-brown background of slightly and superficially oxidized linen?
* Being uncoloured would not necessarily mean those white polysaccharides were chemically unaltered. Glycosidic linkages between the glucose units (alpha- and beta- in starch and cellulose respectively) could be hydrolysed by acid/water causing partial depolymerization, as seems to have been the case in my earlier sulphuric acid experiments, in which the linen fragmented under tension while remaining relatively white. The nitric acid model might account for the observation that Shroud image fibres were more fragile than non-image fibres in Rogers' sticky tape sampling, though some qualifying assumptions would be necessary, e.g. that any starch or other paste used for imaging allowed greater access of nitric acid to the fibre cores, maybe via simple moistening effect, giving more water in which acid could dissolve and accumulate.
Update: Tuesday 10:45 Have just made imprints using (a) egg white and (b) egg yolk (the latter being an approximation to the egg tempera used before Renaissance- era oil paints as a vehicle for powdered pigments.
Am now feeling badly let-down by the Amazon system that allows suppliers to quote hopelessly unspecific delivery times with 12 day windows, and who fail to respond to one's emails. Where's the customer service especially when delivery costs are as much or greater than the value of the article itself?
Update Tuesday 08:46: have just had this terse email:
no its in transit to you nitric has been held up over
new rules but now sorted
Update: Wednesday 15 April
Still no nitric acid (am).
Discovered yesterday that my specialist (largely dormant) Shroud site with WordPress has an out-of-date banner. It made reference to my earlier hypothesis linking thermal scorching off a heated template with the Templars (a scorched-on image being symbolic of the slow-roasting of the Templar leaders - Jacques de Molay, Geoffroi de Charney etc- at the stake in Paris, 1314).
While the direct thermal scorch hypothesis had a lot in its favour, despite any number of attempts to debunk it with crassly-designed experiments guaranteed to "over-scorch", there was one major drawback: one cannot easily monitor the degree of scorching to get the optimum end result. It all tooeasily fails the Goldilocks test (not too hot, not too cold).
The new chemical hypothesis being proposed in its place, based on chemically rather thermally-induced oxidation, albeit with similar end results in terms of carbohydrate caramelization etc, does not suffer that disadvantage. Colour development by exposure to chemical fumes, probably HNO3, allows for colour development to be under minutely-observed second-to-second control. If using HNO3 fumes from a chemical reaction between heated metal salts, it also used what in the 13th/14th centuries was state-of-the-art medieval alchemy - surely a point in its favour, and explaining the failure of we modern day science bods to have spotted sooner the application of long obsolete technology.
I have just this minute replaced the banner with the following:
No, a superficial image on linen, least of all a negative
imprint, need not defy conventional science, and is not an excuse for conjuring
up flashes of radiation or sub-atomic particles from a 2000 year old corpse. Let’s
consider the capabilities of medieval technology – or even alchemy.
Update 17:00, April 15: email message through Amazon from nitric acid supplier:
"it is in transit to you I am trying to find out when"
My reply:
Thank you. You do realize, don't you, that my wife and I are prisoners in our own home,
not knowing when the acid will arrive?
This is quite the worst Amazon experience we have had in some 10 years or more.
It's a form of slow mental torture. Why don't you tell me where you are,
and let me drive over and collect? I'll happily pay twice to be spared this nonsense.
Kind regards
Colin Berry
Update 08:00 Thursday: new email message from nitric acid supplier:
Update 08:00 Thursday: new email message from nitric acid supplier:
yes sorry for that but we are sorting out courier
like amazon do soon sdo you are emailed when it will arrive
My reply:
OK, but it will have to be delivered by the latest date you gave us (Wednesday 22nd April). Why? Because we are travelling after that date, and I'm not willing for nitric acid, no matter how well packaged, to be left with a neighbour. In fact, I doubt whether that would be legal anyway, given its hazardous nature.
Am now looking forward to your email (as are a lot of folk who follow my blog and shroudstory.com who are keen to know what I find with nitric acid). As a teenager, I was able to order acids and other hazardous chemicals from my local pharmacist and take delivery over the counter. Happy days.
Kind regards
Colin Berry
Update 20:30, April 16
Sent this email:
Could you be more definite about three things please?
Update 20:30, April 16
Sent this email:
Could you be more definite about three things please?
First, have you already given the 1 litre of 70% nitric acid
to a courier, or have you not done that yet?
Second: are you absolutely certain I will be sent an email
in advance, specifying the delivery date?
Third: can you confirm that I will receive the acid
by 6pm, Wednesday 22nd April (the latest day agreed for delivery)?
Thank you
Colin Berry
Back to the science: there's another constituent of linen that needs consideration in the fumigation model. It's lignin.
Lignin has lots of condensed aromatic rings and is a known target for nitration. So there are 2 dovetailing approaches. The first is to examine linen fibres under the microscope before and after fumigation with nitric acid. Might the lignin take colour, and if so serve as a potential signature for exposure to the proposed fumes? Second, it would help to have a more lignified system as a reference. The obvious one would be a fibrous woody tissue, but that would not lend itself well to a more realistic "image imprinting", Solution? Imprint with a mush of crushed pear flesh? The gritty bits in the fruit are stone cells - clumps of lignified cells. How will they look under the microscope before and after exposure to nitric fumes?
Update: 18:00 Friday 17 April
Halleluja: The nitric acid has arrived. (I was out when it was delivered so had to collect if from Post Office, after waiting 2 hours for our regular post-lady to return it to depot undelivered!).
Lignin has lots of condensed aromatic rings and is a known target for nitration. So there are 2 dovetailing approaches. The first is to examine linen fibres under the microscope before and after fumigation with nitric acid. Might the lignin take colour, and if so serve as a potential signature for exposure to the proposed fumes? Second, it would help to have a more lignified system as a reference. The obvious one would be a fibrous woody tissue, but that would not lend itself well to a more realistic "image imprinting", Solution? Imprint with a mush of crushed pear flesh? The gritty bits in the fruit are stone cells - clumps of lignified cells. How will they look under the microscope before and after exposure to nitric fumes?
Update: 18:00 Friday 17 April
Halleluja: The nitric acid has arrived. (I was out when it was delivered so had to collect if from Post Office, after waiting 2 hours for our regular post-lady to return it to depot undelivered!).
Experiments are under way. Results initially promising (there being no immediate effect of HNO3 fumes on linen) but then disappointing (no immediate effect of gelatin or flour imprints either). Never mind. These are early days. Maybe it's the liquid acid solution that's needed for development of image, a quick dip maybe, rather than exposure to fumes. Will report preliminary results in a new posting.
Update Saturday 18th April 2015 (for me a red letter day!)
Seems I spoke too soon. The imprint from the hot-water dispersion of wheat flour was left exposed to nitric acid fumes overnight, and removed from its jar this morning for close inspection.
There IS a faint yellow brown imprint of my brass crucifix, and what's more it's against a beige background (the linen having acquired what might be described as an aged look). What's more there's virtually no imprint visible on the reverse side of the fabric! We have ticked a number of important boxes it would seem.
Update Saturday 21:15
Update Saturday 18th April 2015 (for me a red letter day!)
Seems I spoke too soon. The imprint from the hot-water dispersion of wheat flour was left exposed to nitric acid fumes overnight, and removed from its jar this morning for close inspection.
 |
| Imprinted image of brass crucifix onto linen, using viscous gelatinized wheat flour, air dried, then developed overnight in nitric acid fumes. (Photo autocorrected in MS Office Picture Manager). |
There IS a faint yellow brown imprint of my brass crucifix, and what's more it's against a beige background (the linen having acquired what might be described as an aged look). What's more there's virtually no imprint visible on the reverse side of the fabric! We have ticked a number of important boxes it would seem.
Update Saturday 21:15
 |
| Effect of overnight exposure of linen versus cotton to nitric acid fumes. |
More to follow (possibly)?
Update Sunday evening 19 April
Maximal nitration of cotton finally produces nitrocellulose or gun cotton, which is highly combustible (needing no source of external oxygen to decompose rapidly - the nitrate presumably supplying oxygen if needed) What about partial nitration of linen. While it would not be expected to produce explosive 'nitrolinen', it might, just might, make it more sensitive to heat (like hot pokers, fires in cathedrals?). Are you thinking what I'm thinking?
Here's a quick experiment I have just done comparing the effect of heat (from a ceramic hob) on (a) untreated linen (b) linen exposed to nitric acid fumes overnight. Both were then washed and air dried.
You can see one experiment in progress, with control linen (left) and nitric acid treated linen (right). You can also see the result of two completed experiments.
Conclusion: fumigation with nitric acid renders linen more vulnerable to charring. Might we have an explanation for why the Shroud of Turin has been so 'accident prone' where sources of external heat are concerned, even when inside a silver reliquary with limited oxygen? Are we seeing further evidence that the Turin Shroud image was fabricated using early alchemical technology that employed nitric acid fumes?
