“I was quoting Rogers conclusions and asking Thibault for more details concerning Rogers hypothesis (presumably given in a long SSG message) as he suggested,” he writes.
So here it is:
Some years ago, Rogers wrote a very long SSG message to explain step by step his hypothesis and the many parameters. I will try to summarize this message later.
Online, we have only access to part of his book : A Chemist’s Perspective On The Shroud of Turin. Based on preliminary experiments he concluded :
1/When temperature is too high, convection cells are too active, and resolution is low. A body that had cooled would give better resolution than a hot body. I think Rogers first thought high body temperature was needed for two main reasons : vertical convection cells, and a temperature gradient on the shroud, making temperature the main parameter to explain high resolution since he thought reactive amines came from the lungs (and don’t forget he was a thermal analyst). Then he tested his hypothesis, came back on this idea, and admitted a lower body temperature would better suit high resolution. Anisotropic heat flow, may be a second order parameter.
2/The amine must be released slowly. Two much amines badly reduced resolution. Porosity – Adsorption properties of the shroud : a low flow of amines can diffuse through the cloth, a high flow of amines is blocked and flows along the cloth. This is consistent with a slow production of ammonia through hydrolysis of urea on the skin for hours (your article on the origin of the reactive amines).
3/The atmosphere must be cool and still. No external convection flows. Convection blurs the image.
4/An increase in the concentration of reducing saccharides improves resolution. It improves contrast. Indirectly, it allows a lower amount of reactive amines, thus a lower flow.
5/Modern linen that does not contain suitable impurities will not produce an image. According to his Maillard reaction hypothesis, that is an argument against the pcw as the chromophore. The question is, which other parameters are given in his SSG message ? Thank you,