Entering “radiocarbon” and “worst possible” into our favourite search engine brings up about 2000 hits. In the literature, and even more so in broadcast media, it is widely supposed that the people entrusted to select a single representative sample of the Shroud for radiocarbon dating first argued for a hour or so, and finally decided on a site so spectacularly unsuitable that anybody with the most casual acquaintance with the Shroud would have chosen almost anywhere else, if he wasn’t a complete idiot.
Apart from general attacks on “the scientists”, most of the blame is squarely placed on the “textile experts” who, although completely unfamiliar with the Shroud, managed to persuade a number of people who surely should have known better, that this corner was the best place. How they did so is never explained, but the whole thing is generally attributed (mostly by Americans) to Italian incompetence, much to the justified fury of those involved.
The principal reason usually given for not choosing that corner is the evident difference in colour between it and the main body of the Shroud, which is usually supposed to indicate obvious contamination, derived from the fact that that edge of the Shroud seems almost invariably to have been where it was gripped while it was being held up for the adoration of the faithful. However in 2014, at the conference in St Louis entitled ‘The Controversial Intersection of Faith and Science, Ray Schneider demonstrated that the extent of the ‘contamination’ correlated, with a precision of 99.93% with the chronological gradient observed in the radiocarbon datings.1
He declared unequivocally that the contamination was the cause of the gradient, without observing that the relationship was the exact inverse of what he supposed, and the more the contamination, the older appeared the date. In the absence of any good explanation for how the handling of the Shroud by grubby fingered-clerics could have made it appear older rather than younger, rejecting the radiocarbon corner on the basis of this contamination now appears wholly spurious.
Two other reasons, first enumerated by Alan Adler, are equally spurious. In ‘Updating Recent Studies on the Shroud of Turin’2, he wrote “Only a single sample was taken in the lower corner of the main cloth of the frontal image below the so-called sidestrip from the selvage edge in an obviously waterstained area just a few inches from a burn mark.”
In fact, the water stain margin clearly crosses the ‘riserva’ section of the sample extracted from the Shroud, while the area actually tested is distinctly beyond it.
And as for “a few inches from a burn mark”, Adler knew very well that no part of the Shroud is more than “a few inches from a burn mark”, and quite possibly, if he had seen Aldo Guerreschi’s reconstruction3 of the way the Shroud was folded during the 1532 fire, he also knew very well that the radiocarbon corner was almost as far from the principle source of the scorching as it was possible to get. The two dark stripes down the long axis of the Shroud show the folds closest to the fire, while the edges and midline define the parts of the Shroud furthest away. Also, it seems that the major burn holes derive from a single intrusion through the top of the folded cloth. The radiocarbon corner was on the 21st (out of 32) layer down.
These objections are, of course, post hoc attempts to discredit the dating, not sensible reasons for not choosing that site. Although it is certainly true that that corner of the Shroud was among the most handled places, the effect of any possible contamination was considered minimal:
Indeed, far from rejecting the charred areas, the proposal above suggested that they should certainly be used to help date the Shroud.
In fact, far from being a poor place to select, there were good reasons in favour of it. Most importantly, it would do as little extra damage to the Shroud as possible, and not deface the sides or other corners. Although it was then, and is now, generally thought that dating some of the charred material from under the 1354 patches would also be suitable, there was sufficient adherence to the idea that the fire might have affected the date in some quarters for a possible controversy to be avoided. Furthermore, that area had been extensively studied by the 1973 commission, in the person of Belgian textile expert Gilbert Raes, who, unlike any of the scientists since, had been able to study an actual piece of cloth rather than just snippets of thread (Baima Bollone) or individual fibres (Alan Adler and John Heller), and Raes had found nothing controversial.
As for the incompetent textile experts who argued for hours before deciding where to take the sample, we must remember that the only English accounts of the activities in the Sacristy of the Royal Chapel on 21 April 1988 are by people who weren’t there and who didn’t speak Italian. David Sox says:
“Riggi directed what followed. With his earphones and white coat, he became a C.B. DeMille ordering all into position and moving lights and cameras into position. He was filming the great event. […] Tite was with Gonella, Riggi and two textile experts; one from France and the other from Turin. Apparently the latter pointed to the marking of the wound in the side and asked: ‘What’s that large brown patch?’ Obviously his knowledge of the Shroud was rather limited. The two argued with Riggi for more than an hour about where the sample would be taken from.”4
Ian Wilson, writing twenty years later, says:
“Incredibly, it was only at this point that Gonella and his close friend Giovanni Riggi proceeded at length to deliberate on the best location from which to take the sample that was to be apportioned between the three laboratories. Some have claimed that the debate between the two scientists took two hours.”5
Wilson was right in one respect. The story is incredible, and there is no reason to believe it.
The two ‘experts’ were Franco Testore, Professor of Texile Technology at the Polytechnic University of Turin, and Gabriel Vial, a Professor at the Institut des Textiles de Lyon and senior member of the Centre International d’ Étude des Textiles Anciens. Neither of them were unfamiliar with the Shroud, although they had not seen it before. Testore had been invited by Roberto Gonella, the Scientific Advisor to Cardinal Ballestrero of Turin, and Vial had come under the aegis of Jacques Evin, of the Centre de Datation par le Radiocarbone, in Lyons, who had been asked by Prof. Tite of the British Museum if he could find an appropriate control sample. He had done so, extracting threads from the ‘Cope of St Louis d’Anjou’ in Saint Maximin la Sainte Baume, but had been prevented from sending the sample by a postal strike. Giovanni Riggi, who was indeed in overall control of operations, had allocated appropriate time for these experts to become better acquainted with the cloth before the decision was made about where to extract the sample from. His schedule ran:
“6:30 / 7:00 – Opening of the reliquary and arrangement of the Holy Shroud on the work table. The opening and unrolling procedures have already been agreed between G. Riggi and Mons. Caramello.
7:00 – Depending of the availability of H.E. The Cardinal, his arrival would be appropriate at this time. Similarly for the guests. For all of them it is necessary to use the side entrance to the Cathedral, the one that leads directly to the sacristy.
7:15 am / 8:30 am – Observation and discussion on edging. Evaluation of the areas to be opened with the help of documents on the secretarial desk. The work is reserved for the textile experts Prof. Testore, Prof. Vial, the Control Commission and G. Riggi.
8:30 / 9:30 – Unstitching of the prescribed edges, at least two if not three.
9:30 / 11:00 – Physical checks on the fabric. Cutting of the sample or samples from the Shroud. Preparation of the control samples brought by Prof. Tite. Weighing of all samples. Arrangement of all the fragments in Petri dishes on trays, in the Chapter room.”6
There was clearly not going to be a rush, four hours being allocated for the decision. While this sounds somewhat uncertain, I think the principal reason was to allow time for the investigation of both ends of the Shroud, which might have been folded under the surrounding blue silk, in which case a sample could have been extracted without any visible damage when the silk was stitched back in place. Unfortunately, after threads had been unpicked at the dorsal feet end, it was seen that there was no fold, so the Raes corner was selected instead. Such snippets of the video of the proceedings as are available to the public show that the whole procedure was carried out calmly and with no ‘arguing’ at all. At the Paris Symposium in September 1989, both Testore and Vial gave public explanations of the reasons for the selection of the Raes corner, which nobody queried. After the radiocarbon sampling had been carried out, both the experts continued to study the Shroud closely for the rest of the day. As a result of this Gabrial Vial was able to write his definitive paper, ‘The Shroud of Turin, a Technical Study‘7, and Franco Testore carried out numerous experiments involving heat and, with remarkable prescience, lasers, in an attempt to replicate the way the cloth appears to have become discoloured.8
Time to come clean. Although Riggi, Testore and Vial no doubt determined on the Raes corner, condemned by many as the “worst possible” site, and by Alan Adler as “only a few inches from a burn”, entirely independently, they were not the first to suggest it. That honour goes to…
[Wait. We need a slight digression. Although the Shroud is almost invariably depicted with the ventral image to the left, in 1978 the STuRP team investigated it “upside down”, and the index diagrams drawn up to show where the experiments took place were in this configuration.
Photos by Barrie Schwortz
In 1984, STuRP presented their Formal Proposal for Performing Scientific Research on the Shroud of Turin9, consisting of some 26 ‘Work Packages’ to elucidate various aspects of the Shroud left undecided after the 1978 investigation. Number 6 is ‘Dating the Shroud of Turin Using Radiocarbon Analysis, and yes, the selection of samples well within ‘a few inches of a burn mark’, and another ‘in the lower right-hand corner’, widely condemned as the worst possible place to choose, is by none other than Robert Dinegar and Garman Harbottle, of the Shroud of Turin Research Project itself.
It is the only uncharred sample of the main cloth requested.
In January 2020, it was pointed out to me that possible choices of the area for radiocarbon testing long pre-date the 1984 proposal discussed above. That was based on a much earlier document, in which Harry Gove was involved. He wrote to Robert Dinagar on 18 May 1979 suggesting that the Raes sample itself be used. “We would propose to use half of the Raes’ sample taken six years ago from the main body of the shroud.”10
APPENDIX 1
Gove’s suggestion was taken up for the proposal presented formally to STuRP at Los Alamos on 14 October 1979, headed by Robert Dinegar, Raymond Rogers and David Sox. Section V, Recommendations, includes the words: “We will assume that the samples removed in 1973 could be obtained for testing,” specifically, “The 40 mm x 13 mm sample cut from bottom right-hand edge (piece I of the Raes’ report).”11 Interestingly the 1984 proposal discussed above contained no mention of Raes, and seems to be referring to a new sample cut from the same area. Perhaps it was known by then that the Raes sample was unavailable, unusable or unsuitable.
In fact the earliest suggestion as to where to take samples from was made by Walter McCrone, in his earliest response to Ian Wilson, who had written to him out of the blue after reading of his work on the ink of the Vinland Map. On 12 February 1974 McCrone wrote that he was not sure his methods were suitable, “since pigments are almost undoubtedly not involved.” However, he did think that radiocarbon dating could be possible, and that “an almost unnoticeable sample could be taken from some of the badly charred areas.”12 He may not have known at that stage that the Raes sample had been taken, as a few months later, in a more formal proposal sent to Fr Peter Rinaldi on 26 August 1974, he wrote: “Note that even the smaller of the two Shroud linen samples previously examined by Prof. Raes […] is much larger than the 50 mg samples [of different artefacts] already analysed. The larger sample is 110 mg, 5 cm2. Several analyses for date can therefore be determined on small portions of these two samples.”13 This proposal was incorporated into the STuRP suggestions for 1978, but all possibility of radiocarbon dating was firmly quashed by the authorities in Turin, before the investigation was formally submitted.
Although McCrone says no more of his own proposals for radiocarbon dating, they seem to have smouldered on for a while, as he continued to discuss them with David Sox, even after the STuRP investigation in 1978. Sox says that “the investigation Dr McCrone and I made about the possibility of using the Raes’ samples in 1976 ended in failure” but it was clearly discussed in 1980, when McCrone gave a couple of lectures on his pigment findings in Cardiff and London.14 After that, it seems, Sox seems to have joined Harry Gove in the continued attempt to persuade the Turin authorities to recant, as recorded in the Los Alamos proposal above, and McCrone retired from the fray.
APPENDIX 2
In 2022, Joe Marino published a paper at academia.edu 15 in which occurs the only mention I have ever seen of someone objecting to the radiocarbon corner before the test was carried out. This was Dr Henry Polach, Director of the radiocarbon facility at the Australian National University, Canberra, who, in conjuction with Minze Stuiver, was responsible for the early versions of the dendrochronological calibration curves. According to Paul Malony, in a memo entitled ‘A Brief Evaluation of Current Plans to Carbon Date the Shroud of Turin,’ dated 18 April 1988, “Dr. Polach has emphasized that the corner of the Shroud is probably the single most contaminated area of the cloth since it is where the Shroud is most commonly handled – a fact which is confirmed from engravings of past exhibitions of the Shroud.” It doesn’t amount to much, and nobody seems to have taken him seriously, but the comment was made.
Footnotes:
1. Schneider, Raymond, (2014). Dating the Shroud of Turin: Weighing all the Evidence, at shroud.com/pdfs/stlschneiderpaper.pdf
2. Adler, Alan (1996). ‘Updating Recent Studies on the Shroud of Turin’, Archaeological Chemistry, at sindone.info/ADLER.PDF
3. Guerreschi, Aldo, (2002). Photographic and Computer Studies Concerning the Burn and Water Stains Visible on the Shroud and their Historical Consequences, at shroud.com/pdfs/aldo3.pdf
4. Sox, David, (19880. The Shroud Unmasked, Lamp Press
5. Wilson, Ian, (2010). The Shroud: Fresh Light on the 2000-Year Old Mystery, Bantam Books
6. Riggi di Numana, Giovanni, (1988). Handwritten schedule for the day, in the documents released by the British Museum. In Italian, translation mine.
7. Vial, Gabriel, (1991). ‘The Shroud of Turin: A Technical Study’, Shroud Spectrum International, Issue 38/39, at shroud.com/pdfs/ssi3839part4.pdf
8. Ferrero, Franco; Testore, Franco, et al. (1998). ‘Thermal Degradation of Linen Textiles: The Effects of Ageing and Cleaning’, Journal of the Textile Institute, Vol 89, Issue 3, and
Ferrero, Franco; Testore, Franco, et al. (2002). ‘Surface degradation of linen textiles induced by laser treatment: Comparison with electron beam and heat source’, Autex Research Journal 2(3)
9. STuRP, (1984). Formal Proposal for Performing Scientific Research on the Shroud of Turin, at mondosindone.com/Site/documenti/DSS001_02%20-%20Sturp%201984.pdf
10. Letter from Harry Gove to Robert Dinegar, Appendix D of Sox, David, (1981). The Image on the Shroud: Is the Turin Shroud of Forgery?
11. Dinegar, Robert et al. (1979). Radiocarbon Dating of the Holy Shroud of Turin, at newvistas.homestead.com/STURP_C-14_report_1979.pdf
12. Letter from Walter McCrone to Ian Wilson, in McCrone, Walter, (1996). Judgment Day for the Turin Shroud.
13. Proposal from Walter McCrone to Fr Peter Rinaldi, in McCrone, Walter (1996). Judgment Day for the Turin Shroud.
14. Sox, David, (1981). The Image on the Shroud.
15. Marino, Joe, ‘Observations on the Turin Shroud 1988 C-14 Dating from the Correspondences of the Archaeologist Paul C. Maloney,’ at academia.edu.