I have experiments going right now to see if I can't improve on the somewhat blurred and indistinct image obtained so far off my brass crucifix. If I had access to a larger fumigation chamber that safely contained fumes within my garage, I'd be attempting to image off myself (IMPRINT only!) starting with a hand say (though a finger or two might be possible within the stoppered bottles (jars?) being used at present.
Here a picture taken an hour or so ago of the current experiments out in the sunshine, on the patio table.
They are now safely back in the garage and the test linen strips will be removed and photographed tomorrow (results on this posting). I'm not sure if the brown fumes of NO2 are evidence of the nitric acid quickly finding components to oxidize (hemicelluloses?) or merely photodissociation of HNO3 in the sunshine. I'll need to set up extra jars to test this and other 'good housekeeping' hypotheses. One is still on a steep learning curve with the new system.
While twiddling my thumbs, waiting for the images to develop in those jars (yes, let's call them jars, being fairly wide-mouthed) I've been thinking some more about the mechanics of fumigation, performed medieval-style. Some might consider it a tall order (or wide order?) to fumigate a 4.4 x 1.1 metres length of linen. I'd previously suggested it was done 'landscape' rather than 'portrait' orientation, if only to suggest a raison d'etre for the peculiar side strip removal and re-attachment (see previous posting).
Well, I've been having second thoughts, as you will now see from some simple modelling with folding to get a compact package for fumigation.
That's an image of the TS you see above, printed out onto A4 paper, with the edges guillotined. The ends corresponding with frontal feet (left) and dorsal feet (right) have been labelled.
Here's the same after folding lengthwise and then width-wise. This would now represent a more convenient package for fumigation if suspended at the gathered feet end (top) , ie. 2m x 0.5 metres approx.
Here's the same, suspended by a thread. Note that the imprinted surfaces are all freely exposed to the fumigant. So too, though more cramped by converging surfaces, is the reverse non-image side, except possibly for the crease area between frontal and dorsal head.
Given that our medieval forbears built magnificent cathedrals that still stand to this day, it seems reasonable to suppose that a suitable chamber could be found for exposing the above package to nitric acid fumes. The latter was produced from high-temperature calcining of a mixture of Cyprus vitriol (copper sulphate)/alum (potassium aluminium sulphate) / saltpetre (potassium nitrate). That's the reaction mixture prescribed by the 13th century alchemist Pseudo-Geber, possibly one and the same as the Franciscan monk, Paul of Taranto (see my previous posting). The nitric acid (HNO3) fumes from the retort could have been used directly, or could have been condensed into a cooled receiving flask, and then reheated to produce the same HNO3 at leisure (obviously more convenient to do in separate steps).
A suitable chamber for fumigation? Given the compact dimensions from my folding experiment, maybe a small brick built kiln of some kind, or reinforced clay-built enclosure, taller than it is wide. Maybe the side strip can be re-accommodated within this 'tall' configuration, maybe not.
See also my comments placed on a shroudstory.com posting for more details of my thinking re the potentiality of this current 'fumigation' model. There's much to be done, many TS characteristics to be matched (image superficiality, non-fluorescence etc) but I'm quietly becoming more confident by the day, by the hour that this might finally be the answer that has eluded us bumbling science bods for so long...
Update: Monday 13:45:
Somewhere I've read that the head image on the TS is 10% (?) more intense than the rest of body. (will try to track down a reference).
Yup. Located. 2005 Dallas meeting.
"The luminance level of the head image in the positive photograph of Durante (2000) is 10% and more lower (darker) than that of the whole body image(Moran 2002)"
Conversely, we all know that the feet at the opposite end on both frontal and dorsal halves are scarcely imaged at all.
The proposed geometry for fumigation shown above offers an immediate explanation. The head is close to the source of acid-fumes, fed in from the lower end, while the feet are furthest removed. In other words, the difference in image intensity is maybe not the result of an imbalance at the imprinting stage (difficult to explain) but an imbalance at the stage of image development.
Update Tuesday 21 April
While waiting for my latest imprinted linen samples to develop in their fumigation chamber, I've been taking a glance at Dan Porter's shroudstory site. The current posting has a thumbnail picture of an unused portion of the Arizona sample for radiocarbon testing.
It's credited to "STERA" 2012 , and sure enough one can find Barrie Schwortz's account on his internet site of how he was invited back to the Arizona lab to take that and other close-up pictures.
Looking at it, one would hardly credit it was linen, even 2000 year old linen, not that I'm an expert where the latter is concerned or even medieval linen. But if anyone had shown me that sample 'blind' and asked me to identify its origin, I'd have said it was jute sacking.
But now I have an advantage over others. I have seen what nitric acid fumes do to linen, turning them a beige-colour, though admittedly not quite the honey-coloured appearance you see above. I've also seen what happens when one places nitrated linen on a hot ring - it chars much faster and more extensively than control untreated linen. Here's that same snapshot again:
Are we seeing the 'real' reasons why the present Shroud in Turin is extensively damaged by "hot pokers" and fierce fires in cathedrals? Might it have been less damaged by either of those if it had been plain untreated linen, not nitrated linen as I now propose?
Might the honey-coloured TS linen be the colour it is on account of the "relic" having been produced by my novel two step-process - imprinting off a 3D subject with flour paste, followed by chemical development with nitric acid fumes?
Looking at that STERA image above has just reminded me of two further pieces of evidence that fit with the new hypothesis:
1. The absence of vanillin (or, as this blogger prefers to call it, potential vanillin) in the TS, cited by STURP's Ray Rogers as evidence of the TS being much older than the medieval dating.
2. The more recent work by Fanti and his colleagues on shed fibres retained between TS and its backing Holland cloth that were aspirated/harvested at the time of the 2002 'restoration'. Those fibres they claim have mechanical and spectral properties that make them closer to 2000 than 700 years old.
All is explained in the new model. Nitric acid fumes, being powerfully oxidizing (among other things) do in a few hours what would require centuries to achieve by slow atmospheric oxidation. The fumigation did not just convert an imprinted flour image into a pseudo-sweat imprint left on Joseph of Arimathea's expensive linen. It gave the entire bolt of fabric an aged appearance, like that which one sees in the Schwortz photograph above. Indeed, it may have been knowledge of what the 'new-fangled' nitric acid of the 13th/14th century did to linen and other fabrics, and then to skin and other organic materials that planted the idea in someone's head that nitric acid could be used to create a sensational new entry for the booming market in "newly-discovered" holy relics.
Speaking of Ray Rogers (may he rest in peace) here's something this blogger wrote back in June 2012 regarding his diffusion/Maillard model (that lives on in numerous sindonological sites to this day, despite having scarcely a shred of scientific evidence in its favour). Note my words in red:
"There is other evidence too that the assumption by Rogers that the image is in an impurity layer (largely based it seems on the writings of Pliny), formed by a Maillard reaction between supposed reducing sugars in the impurities and volatile amines from post mortem decay (cadaverine, putrescine etc) is ruled out by Rogers’ own observation in the same paper that the Shroud’s image-bearing areas are not enriched in nitrogen. (All amines contain nitrogen, the amine group being -NH2)"
Have I now been hoist by my own petard? The model proposed here also requires there to be extra nitrogen, indeed extraneous nitrogen in Shroud image areas, as does/did Rogers' credulity-stretching model.
I'll be back later today to address this problem. Those impatient to know the (possible) explanation for a nitrogen anomaly can get some of it in the conversation I had with Adrie van der Hoeven on the posting preceding this one (see Comments).
If you search for (nitrogen analysis methods) as I have just done, all 10 returns on the first page refer directly or indirectly to the Kjeldahl method. But while that measures most nitrogen in human, animal and plant tissues (proteins, peptides, amine and amide nitrogen) it does NOT measure nitrates, whether as nitro substituents (N bonded directly to C as in "true" nitro-derivatives, i.e. -C-NO2) or as nitrate esters, e.g. -C-O-NO2, with an oxygen bridge between C and N. But was the TS nitrogen measured by this time-honoured method? The Kjeldahl procedure is traditional wet chemistry, usually done for materials where there is no limitation on sample size. OK, there's a micro-Kjeldahl variant, but I for one can't say as I ever recall having seen the K word linked to the Shroud. So how did Rogers and others determine the nitrogen? X-ray fluorescence? One hopes that the absence of a peak on that kind of scan was not taken to mean nitrogen was missing (as elsewhere we see a STURP claim for the absence of aluminium). X-ray fluorescence is generally reckoned to allow detection of elements above chlorine (atomic number 17). Nitrogen is element number 7 (far too small). Aluminium is element number 13, still too small. Was a third method used by STURP to determine N? I doubt it, but stand to be corrected.
Update Tuesday 13:20
Here's the very first attempt to imprint of my own hand, using the new two-step flour gel/nitric acid technology. I used the back (top surface) of the left hand to be precise, and the right one to apply pressure to the overlying linen, with gel-painted hand underneath.
As I say, these are early days. There is much optimization needing to be done, but the method works in principle. The circled area is probably due to excessive wrap-around, i.e. moulding the linen to the vertical side of the hand. In future it must be vertically downward pressure, so as to restrict the imaging to the highest relief, and producing a quasi-bas relief, despite the fully 3D nature of the 'template'.
Taking stock: flour was chosen as initial prime-focus imprinting medium for historical and chemical reasons. First, it's been a component of the human diet, cooked especially, not just for centuries but millennia. Second, while mainly starch, there's a reasonable proportion of protein too (approx.10%) so one covers one's bets where the developing agent is concerned. Nitric acid will tend to dehydrate /oxidize carbohydrates, whether starch or non-starch polysaccharides, to brown caramelised products, with the added possibility of yellow nitration products too (see previous postings for the propensity of conc.nitric acid to give the so-called xanthoproteic reaction with aromatic side chains of proteins which are bright yellow.
The flour works in principle, but it's slow, and the final images are not quite as distinct as one might wish against the off-white background.
So what are the alternatives? Egg white has been tested, and gives a prominent yellow imprint, as expected, albeit requiring overnight development. But there is reverse-side colour as well, which one hardly sees with the gelatinized flour pastes. So it's thinking cap on : what else might have been tried on a trial-and-error basis? Might one need to test mixtures, say of wheat flour and additional protein, the latter in a form with little tendency to migrate through the weave of the cloth.
Update: 17:00 Tuesday 21 April 2015
Oops. I (nearly) gave up too soon on that hand imprint, the one reported above that initially looked so unpromising. Well, it's been further processed (Step 3) and the result is methinks deserving of a new posting all to itself. What did I do that made the difference between (possible) success and abject failure? Answer - I washed out and neutralized the excess of nitric acid remaining in the fabric after fumigation (as our proposed medieval alchemically-literate relic-forgers might have done).
Yes, there will be a new posting, this very evening, once that 3-step imprinted linen is fully dry and re-photographed.
Step 1: imprint off 3D template (possibly a real person, living or dead OR an effigy thereof in wood, stone, clay etc) painted with heat-gelatinized white flour.
Step 2. Develop the proto-imageby exposing to nitric acid (HNO3) fumes
Step3. Neutralise the unreacted acid in the fibres (e.g. by dusting with chalk, or rinsing with lime water).