Heard from Paolo Di Lazzaro that “Alan Boyle was kind enough to update his post adding my reply to Nickell’s claims.” It is captioned, “Update for 3:50 p.m. ET Dec. 26: Di Lazzaro sent this response to Nickell’s questions via email,” and reads as follows:
"In 1978, several sticky tapes were used to sample the Shroud in different points of the body image. When the image fibers were pulled out of the adhesive, their colored coatings had been stripped off the fiber and remained in the adhesive. These coatings were independently analyzed by Profs. Alan Adler and Ray Rogers, and all of them were too thin to measure accurately with a standard optical microscope. This means the thickness of all coatings was smaller than the visible light wavelength, say thinner than 0.6 micrometer.
"Recently, these results have been confirmed by a direct measurement of another fiber, showing the thickness of the colored coating around the fiber is about 0.2 micrometer. As a consequence, there is quite a good probability most of the image fibers throughout the body image have a coloration depth smaller than 0.6 micrometers.
"Prof. Garlaschelli claimed he obtained ‘a superficial coloration’ without mentioning ‘how much’ superficial. Is it 100 micrometers thick? 10 micrometers? One micrometer? Nobody knows. I asked chemists [who are] colleagues at ENEA, and they told me it is impossible to obtain a coloration depth smaller than 10 to 20 micrometers with the chemicals used by Prof. Garlaschelli. This fact alone means the results of Garlaschelli are not comparable with the Shroud image. Mr. Nickell may be interested to know Prof. Garlaschelli refused to reply the letter sent to the editor of JIST (the journal that published his results) where several points of his work were criticized, including the lack of a measurement of the coloration depth.
"Coming to the question of Mr. Nickell: We never claimed to have reproduced the whole Shroud image. We were interested to gain a deeper insight into the physical and chemical processes that generated such an unusual image. And we were successful to find photochemistry processes that are able to generate a Shroud-like coloration of linen fibers.
"Concerning Occam’s razor, I am a scientist, and when I wish to understand a phenomenon, seeking for a scientific explanation, I use microscopes, spectrometers, image detectors and other laboratory tools. I see Mr. Nickell prefers using philosophical instruments like the medieval Occam’s razor, a theory proposed in the 14th century. Each of us is free to choose the most familiar tool to find answers."