The non-fluorescent body image on the Shroud is a pale sepia colour. It may or may not have been the result of mild scorching (I happen to believe it is a light scorch). But the fluorescent, heavily charred regions on the Shroud are the result the 1532 fire etc. There is no inconsistency whatsoever between these two findings. All that remains to be done is to offer an explanation as to why one fluoresces and the other does not, ensuring that it is a TESTABLE and potentially FALSIFIABLE explanation, i.e. a SCIENTIFIC explanation.
OK, so here goes. Here is my scientific explanation:
The 1532 fire exposed the linen to high temperatures, ones that charred i.e. carbonized the carbohydrates, notably the cellulose. Carbonization of cellulose is known to proceed via intermediates that have aromatic ring systems (see the recent paper by Sevilla and Fuertes, 2009)
Note the aromatic benzenoid ring systems, prime candidates for fluorescence under uv radiation. Reminder: the margins of the heavily-scorched, indeed carbonized, holes in the Shroud linen(1532 fire etc) exhibit a red fluorescence.
Aromatic ring systems with delocalisation of π-bonding p- type electron clouds frequently fluoresce under ultraviolet light.
However, the temperatures that produced the sepia image on the Shroud were not high enough to char and carbonize cellulose. Indeed, they may not have been high enough to affect the cellulose at all. They may have affected primarily or exclusively the chemicallymore susceptible hemicelluloses of the primary cell wall (accounting for the superficiality of the Shroud image).
PS It’s instructive to read Barrie Schwortz’s two comments in full.
Quote (1 of 2):
“I think everyone is forgetting an important fact. The idea of the Shroud image being the product of scorches caused by a heated metal statue has been around for a long time (since the STURP days), and was first proposed by Joe Nickel, avowed atheist and Shroud skeptic.
Since the color of the image is very similar to the color of the scorches, STURP understood the need to test this theory and performed specific experiments for that purpose. A primary test was to photograph the Shroud using ultraviolet fluorescence photography, since true scorches on linen will always fluoresce in the red. As there are many documented scorches on the Shroud from the 1532 fire, testing this was not difficult and the results of the tests were published in this peer reviewed reference:
Miller, V.D. and S.F. Pellicori, “Ultraviolet Fluorescence Photography of the Shroud of Turin,” Journal of Biological Photography, Vol. 49, No. 3, 1981, pp. 71-85.
Every documented scorch on the Shroud fluoresced in the red, as expected. However, the image did NOT fluoresce and in fact, even quenched the background fluorescence in the image areas. The only conclusion possible from these observations is that the Shroud image is NOT the product of scorched or heated linen.”
Quote (2 of 2) He kept the real stinker till last:
Sadly, that’s why I don’t post to blogs very often. I don’t have time to waste debating folks who simply choose to ignore the published science. They obviously have already made up their minds so why bother? Perhaps they have more time on their hands than I do, but I am not interested in arguing for the sake of argument. That is why I never try to convince anyone of anything. Frankly, I don’t really care what this gentleman thinks and will leave him in your and Dan Porter’s able hands.
The article I referred to was published in a highly respected scientific journal. However, due to copyright restrictions, I do not have the right to distribute or publish the article or the UV fluorescence photographs it contains in a public forum. The photographs are all copyrighted to Vern Miller.
However, there is a great Table in the paper that makes the very specific comparisons you have been discussing in this forum, so I highlighted them in yellow and posted a jpeg image of the table to this link:
Perhaps that will be helpful to your skeptic (but I doubt it). Have a great weekend!
[You can also click on the picture of the table to the right]
Note his preoccupation with copyright issues, even when discussing a crucial scientific point re the Shroud’s authenticity. Has BS, described today as “copyright expert” (oh yes indeed) never heard of “fair use” waivers– designed to ensure that copyright is never used to gag genuine disinterested researchers, like this one?
As I said in my last post, what BS did in February was nothing less than a guerrilla hit-and-run tactic, deploying what he thought was good STURP science, but which in his hands translated into flawed logic and defective science.
Maybe BS should stick to his photography – jealously guarding and indeed extending that copyright portfolio of his and STERA’s – leaving the disinterested science to us disinterested scientists.
Technical footnote: what a delightful and unexpected mechanism that is for carbonisation of cellulose. Ask anyone how they pictured the process at the molecular level, and I’m willing to bet they would imagine it to be one in which the hydrogen and oxygen are driven off to leave a carbon skeleton. In other words 0ne polymeric matrix – cellulose fibres – gradually transforms into another – charcoal. But as the diagram reveals, that is not the mechanism: cellulose becomes fragmented into small reactive molecules with 5 or 6 membered rings, and the latter then gradually undergo condensation reactions to produce tars and resins, and finally a ‘hydrochar’ particle. Chemistry is full of surprises.