A Carbon Dating Catastrophe with the Shroud of Turin

2008 News:  Shroud of Turin for Journalists

The carbon 14 dating conducted in 1988 seemed conclusive: The Shroud of Turin was not, as millions of people believed, the authentic burial Shroud of Jesus. Nature, the international weekly journal of science, published an article about the carbon 14 dating coauthored by twenty-one scientists from the University of Oxford, the University of Arizona, the Institut für Mittelenergiephysik in Zurich, Columbia University, and the British Museum. The conclusion according to the Nature article was clear:

The results of radiocarbon measurements at Arizona, Oxford and Zurich yield a calibrated calendar age range with at least 95 confidence for the linen of the Shroud of Turin of AD 1260 - 1390 (rounded down/up to nearest 10 yr). These results therefore provide conclusive evidence that the linen of the Shroud of Turin is mediaeval.

New information recently discussed in National Geographic News (April 9, 2004), in a PBS documentary ("Secrets of the Dead: The Shroud of Turin," April 7, 2004) and in several recent papers show that the Shroud of Turin has not been successfully carbon 14 dated.  It seems that what was tested was nothing more than a mixture of old thread and new thread from a medieval patch (historical documentation suggests that the repair may have been made in 1530 or 1531).

M. Sue Benford and Joseph Marino, in collaboration with number of textile experts, identified clear evidence of medieval mending on the Shroud. A patch was expertly sewn to or rewoven into the fabric to repair a damaged edge. It was from this patchquite likely nothing more than a piece of medieval cloth—that the samples were taken. From documenting photographs of the sample areas, the textile experts identified enough newer thread to permit Ronald Hatfield, of the prestigious carbon 14 dating firm Beta Analytic, to estimate that the true date of the cloth is much olderperhaps even 1st century. See:

[PDF] Evidence for the Skewing of the C-14 Dating of the Shroud of Turin Due To Repairs by Joseph G. Marino and M. Sue Benford

[PDF] Textile Evidence Supports Skewed Radiocarbon Date of Shroud of Turin by M. Sue Benford and Joseph G. Marino

Historical Support of a 16th Century Restoration in the Shroud C-14 Sample Area by M. Sue Benford and Joseph G. Marino with special contribution by Robert Buden

Independently, Anna Arnoldi of the University of Milan and Raymond N. Rogers, a Fellow of the University of California Los Alamos National Laboratory have explored the chemical nature of the sample area. They have confirmed the finding of Benford and Marino. Ultraviolet photography and spectral analysis show that the area from which the samples were taken was chemically unlike the rest of the cloth. Chemical analysis reveals the presence of Madder root dye and an aluminum oxide mordant (a reagent that fixes dyes to textiles) not found elsewhere on Shroud. Medieval artisans often dyed threads in this manner when mending damaged tapestries. This was simply to make the repairs less noticeable. The presence of Madder root and mordant suggests that the Shroud was mended in this way.

Microchemical tests also reveal vanillin (C8H8O3 or 4-hydroxy-3-methoxybenzaldehyde) in an area of the cloth from which the carbon 14 sample were cut. But the rest of the cloth does not test positive for vanillin.  Vanillin is produced by the thermal decomposition of lignin, a complex polymer, a non-carbohydrate constituent of plant material including flax. Found in medieval materials but not in much older cloths, it diminishes and disappears with time. For instance, the wrappings of the Dead Sea scrolls do not test positive for vanillin. See:

[PDF] Scientific Method Applied to the Shroud of Turin: A Review by Raymond N. Rogers and Anna Arnoldi

This is an important find. It suggests that the tested samples were possibly much newer and it underscores that the chemical nature of the carbon 14 samples and the main part of the cloth are outstandingly different.

This photograph, by Vern Miller, was taken before the samples for carbon 14 testing were cut from the Shroud. It was taken with a heavily-filtered ultraviolet lighting that did not emit any visible light at all. All of the light you see in the photograph was produced by the fluorescence of chemical compounds on the Shroud. Any variations in color and brightness are a direct result of the chemical composition.

According to Ray Rogers:

I believe that this is one of the most important photographs of the Shroud that has been taken. It shows the fluorescence of the area of the radiocarbon sample. It proves that the radiocarbon sample did not have the same chemical composition as the rest of the cloth. This is a fact - not an interpretation. . .

Notice that the entire area above the Raes sample and along the seam is darker than the main part of the cloth. It does not fluoresce. . .Its chemical composition is different from the Shroud. That is exactly the area sampled for the 1988 dating fiasco. . .

The radiocarbon sample was invalid. No strange, magical events are needed to explain the invalid date. I do not know what the real date is, but I know the sample used in 1988 did not yield a valid date. The poor preparation for sampling in 1988, the poor verification of the sample, the failure to follow written protocols, and the unrealistic claims made about "unreliable" radiocarbon dating have done great damage.

Archeologists know well that carbon 14 testing is best suited for testing things that have been undisturbed and well protected from natural or manufactured contamination. Because of this problem and because unexplained anomalies in the measurements often occur, corroborating evidence of another kind is sought. For instance, an archeologist might try to compare the cloth with other linen examples from antiquity.

A significant fact is that the yarn was bleached before the cloth was woven. This is not how linen was produced in Europe during the time in question. There and then, the entire linen was bleached after weaving. More ancient linen was manufactured as described by Pliny the Elder: individual hanks of yarn were bleached and dried before weaving. This produced batches of thread with slightly different off-white coloration.  With lighting from behind, X-ray-transmission, ultraviolet light and contrast-enhanced photography we can see discrete bands of yarn with different visual characteristics (x-ray densities and corresponding color densities).  Some areas show darker warp yarns and some show darker weft yarns.  In places bands of darker or lighter color cross producing plaid effect. Archeologically speaking, the cloth of the Shroud was not produced when the carbon 14 testing determined that it was.



© 2004 Daniel R. Porter, Bronxville, New York