Paolo Di Lazzaro very kindly provided a helpful answer to yesterday’s posting, A Reason to Doubt the Image Was Formed By Radiation (see editing note*):
[Your friend]’s question is legitimate, like almost all questions, but it denotes a not updated knowledge of published scientific data and results obtained in the last ten years. We answered [your friend]’s question in our paper published in Applied Optics in 2012, see Superficial and Shroud-like coloration of linen by short laser pulses in the vacuum ultraviolet.
More recently, we were even more explicit, see reference  in the paper Shroud like coloration of linen, conservation measures and perception of patterns onto the Shroud of Turin.
In short, the sentences of Rogers were triggered by negative experimental results of excimer laser irradiations on linen (as well as of particle irradiations). Rogers wrote "Experiments we did with pulsed ultraviolet lasers on linen resulted in ablation and destructive shock waves. Samples often were converted into a little amorphous powder and gas”. (Testing the Jackson “Theory” of Image Formation)
Moreover, he wrote “Very intense, 50-ns-long bursts of UV ablated the cloth surface, and the samples were reduced to a cloud of very fine particles. We could not get a color with a flash of light.” (Scientific Method Applied to the Shroud of Turin: A Review)
Few years later, in 2006 we have experimentally shown the above Rogers’ statements are simply not true. We obtained a superficial coloration of linen by UV laser beam without destroying the linen, nor altering linen’s structure. Does it means Rogers’ results were wrong? No, because we experienced the same Rogers’ failure when using longer than 50-ns laser pulsewidth. Rogers and his coworkers just used a too long laser pulsewidth, and the wrong combination of intensity/fluence/ number of shots to obtain a Shroud-like coloration. Details on why it happened are given in Shroud like coloration of linen, conservation measures and perception of patterns onto the Shroud of Turin.
This is normal in science, one performs an experiment with negative results, and later another one finds the good combination of parameters to achieve the desired results. I am sure a honest scientist as Rogers was, would have recognized his "overestimation" of radiation results.
And this is the main reason why a wise scientist never writes his/her results are the "definitive proof" or "provide conclusive evidence" of something. Every result is obtained in good faith (bona fide) until another scientist proves otherwise. Unfortunately not all scientists are wise, see e.g. the conclusions in the Nature’ paper on Shroud radiodatation.
Hope this may clarify the issue, ….
All the best
*Editing note: To better fit in this blog, I took the liberty of replacing long http-ish links with the actual titles of papers and made the titles linkable. Most browsers will show you the original link if you hold your mouse-cursor over the title. I also replaced my friends name in the letter since it has not been revealed here.
“We obtained a superficial coloration of linen by UV laser beam without destroying the linen, nor altering linen’s structure.”
Not altering linen’s structure? Really?
“We cantherefore infer that short and high-intensity UV pulses change the crystalline structure of cellulose in a similar manner as aging and low-intensity radiation (radon, natural radioactivity, secondary parti-cles from cosmic rays) accumulated in a long-termperiod do.”
That’s precisely Rogers’ point. He could not see any difference between image fibers and non image fibers.
So, Dr Di Lazzaro, high intensity UV pulses don’t alter linen’s structure? Rogers was wrong?
VERY GOOD QUESTIONS and I think asking them gives us already the answer! Damn I would wish Rogers would still be alive to make a proper comparison between the colored fibers of his Shroud samples and Di Lazzaro’s colored samples. I’M 100% CONVINCED he would have come up with major différences, not only on the physical level (we already know there are since Rogers was convinced the image chromophore was NOT located in the primary cell wall or any other part of the linen fiber structure), but also on the chemical level…
And here are two more good questions for Mr. Di Lazzaro :
1- When you got a coloration result that was close to the Shroud color (close but, if we believe Rogers, not identical at all), what was the distance between your laser and the sample? If the distance was more than 4 cm, then your result is clearly NOT identical the the Shroud, because we know for a fact that the image formation process was unable to produce any visible color beyond 4 cm.
2- Have you tried the same experiment (with the same exact source of energy) with the laser being located in direct-contact with the target (i.e. the linen sample) and then to compare the coloration result you could get with the one you already got (which I have to guess was obtained with a laser not located in direct-contact with the sample)? In all logic, you should see some evident differences between the two results…
Also, I would like to react concerning one claim made by Mr. Di Lazzaro that I hear all the time from those who contest Rogers’ conclusions that the image on the Shroud could not have been produced by any type of energetic radiation, which can be summarized like this : Rogers based his claim solely on the experiments he did with some high-intensity sources of energies. This is a WRONG statement! In his book and in some of his papers, Rogers brought a lot of others scientific reasons to explain why, in any way, the Shroud image could have been produced by any type of energetic radiations. Here are some of those reasons (just a few among others) that can all be found in my paper “Raymond N. Rogers’ observations and conclusions concerning the body image that is visible on the Shroud of Turin” :
1- “An average flax fiber is 10-20 microns in diameter, and some lower fibers are colored in image areas. Any radiation that colored the circumference of two, superimposed fibers would have to penetrate at least 20-40 microns of cellulose. Radiation that penetrated the entire 10-20 microns-diameter of a fiber would certainly affect the entire volume of the fiber, including the walls of the medulla (the cylindrical void in the center of the fiber). All image fibers (from the Shroud) show color on their outer surfaces, but the body of the fiber and the walls of the medulla are not colored.”
2- “We had found starch fractions on the cloth during chemical testing. I had to hypothesize that image color had formed in a layer of impurities. I studied the chemical kinetics of the impurity materials and conclude that it was improbable that the impurities had been scorched by heat or any radiation source: the crystal structure of the flax image fibers was no more defective than non-image fibers. It would take very good temperature control specifically to scorch impurities without producing some defects in the cellulose. ” Note that when Rogers wrote « cellulose », he was obviously reffering to the whole linen fiber including the primary cell wall.”
3- “All parts of the Shroud are the same age, and all parts have been stored in the same location through the centuries. Therefore, all parts should have been exposed to the same kinds and amounts of (natural) radiation. Any additional radiation effects found in image areas would indicate excess radiation in that location. Direct comparison between image and non-image parts of the Shroud show exactly the same amounts and types of radiation damage in the two types of areas. This suggests that the image was not produced by any mechanism that involved heat, light, or ionizing radiation.”
4- “All parts of a cloth will show the same (natural) radiation damage, unless there has been specific radiation in limited areas. Image areas (of the Shroud) do not show any evidence for excess radiation.”
5- “The primary result of irradiation of cloth with energetic photons is heat. The blood was never heated to a temperature concordant with an intense flux of vacuum ultraviolet photons.”
6- “The blood could be removed with proteolytic enzymes. The blood had not been cross-linked by irradiation. It is extremely unlikely that any form of radiation interacted with the cloth.”
Isn’t that enough? Coming from someone who was a real expert in radiation and who had the opportunity to study the Shroud up close and personal, that’s good enough for me… We must look elsewhere than energetic radiations to find the right explanation for the image on the Shroud. Important note : This statement of mine doesn’t mean the Maillard reaction hypothesis of Rogers is the solution to the image formation…
Last thing : Rogers’ paper about radiation effect was a paper he wrote for the general public. The few examples of coloration experiments he did with energetic radiations that we find in it must never been understand has being the only (or even the primary) thing on which Rogers based his conclusion that the Shroud image is not the product of energetic radiation… The few experiments he did were only intent to show clear examples of the general effects of energetic radiations on linen fibers.
Hi Yannick, there are many questions to ask, but here we’re stuck to the very first one, clearly put by Dan:
“Has this ever really been refuted or disputed or was it simply ignored as inconvenient? Is the linen coloration obtained by ENEA scientists different?”
“This” refering to a paper by Rogers, https://www.shroud.com/pdfs/rogers8.pdf , looking at the effects of radiation on flax fibers.
Dan, though not a scientist, has a good idea of the big picture and has precisely quoted Rogers:
“Direct comparisons between image and non-image parts of the shroud show exactly the same amounts and types of radiation damage in the two types of areas (e.g., figures 7 and 8). This suggests that the image was not produced by any mechanism that involved heat, light, or ionizing radiation.”
Di Lazzaro uses bursts of UV light and creates radiation damage ( see fig. 12 https://www.academia.edu/3478909/Superficial_and_Shroud-like_coloration_of_linen_by_short_laser_pulses_in_the_vacuum_ultraviolet ). We can fairly say that this radiation damage alters the linen’s structure.
Now, let’s read Di Lazzaro’s answer and see how he dodges the question, again, simply ignoring Dan’s quote and dwelling on another experience. Needless to say, i don’t consider his answer very helpful.
AMEN. I agree with you 100%.
Nevertheless, it would be great if Di Lazzaro could dare to answer my good questions! I think that if he would do this, we would have other reasons to discard his UV hypothesis as being able to explain the image formation on the Shroud…
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