Why We May Believe the Shroud is Not Medieval

There are valid reasons to question the conclusions based on the evidence described in the previous post, even with the results of the carbon 14 tests. Conducted by three of the most reputable radiocarbon dating laboratories in the world, the carbon tests have been credibly challenged by other scientists, so that many scholars agree that they can no longer be deemed definitive. The laboratories did the tests properly. There is little doubt about that. But there is now credible evidence that the samples cut from the Shroud and provided to the laboratories were contaminated.

We cannot blame the labs. They had no way of knowing. The contamination may have been the fault of the Poor Clare nuns who mended the cloth when it was in their possession in the 16th century, or of some master weaver in their employ who wove new thread into the cloth during repairs. We know from other repaired tapestries that medieval weavers were skilled at the art of “French Weaving,” (which is now commonly called invisible weaving). Warp and weft threads were even spun by hand and dyed to match the original thread of a tapestry.

Evidence of contamination comes from more recent research by Raymond Rogers, Anna Arnoldi, P.H. Smith and others. Rogers, a Laboratory Fellow at Los Alamos National Laboratory, found a rubbery vegetable substance on threads adjacent to where the carbon 14 samples were taken, determined to likely be gum arabic. It was common practice to use gum arabic to hold threads during weaving repairs in the Middle Ages. Rogers also found dyes extracted from the Madder root used with the gum arabic. According to Rogers, “[newer threads] were colored for a purpose using technology that was not used in Italy before the 13th Century or in France before the 16th Century, about the time the time the Shroud was moved to Turin from France.” Rogers has also found a spliced thread, likely of old and new material, among sample threads.

In a new and very decisive paper on the subject, “Scientific Method Applied to the Shroud Of Turin: A Review,” Raymond N. Rogers, and Anna Arnoldi of the University of Milan wrote:

Rogers and Arnoldi: The combined evidence from chemistry, cotton content, technology, photography, and residual lignin proves that the material of the main part of the Shroud is significantly different from the radiocarbon sampling area. The validity of the radiocarbon sample must be questioned with regard to dating the production of the main part of the cloth. A rigorous application of Scientific Method would demand a confirmation of the date with a better selection of samples.

P.H Smith, while examining threads from the Shroud, at the Oxford Laboratory, found similar indication of contamination. An article entitled “Rogue Fibers Found in Shroud,” published in Textile Horizons in 1988, Smith speaks of his discovery of “a fine dark yellow strand [of cotton] possibly of Egyptian origin, and quite old . . . it may have been used for repairs at some time in the past, or simply bound in when the linen fabric was woven.”

A 1978 Ultraviolet-fluorescence photograph of a small section of the Shroud is very revealing. Certain materials when subjected to UV light fluoresce, thus emitting visible light. (UV light is outside the range of visible light and is often referred to as black light). By filtering the light source to eliminate any possible visible light and by filtering the camera lens to ensure that no UV light reached the film, only the visible light caused by fluorescence was captured in the photograph. All of the color seen in the photograph was the direct result of the fluorescence of chemical compounds on the Shroud. Variations in color and brightness show variations in chemical composition. As is clearly visible, most of the Shroud’s material fluoresces. Notice, however, a long triangular shaped section, curved slightly along the top slope, along the bottom edge of the Shroud. It fluoresces very little and appears dark brown. According to Rogers, this is clear proof that this area of the Shroud does not have the same chemical composition as the original material. It is from this area that the samples were cut for the carbon 14 tests. They were cut from the dark area immediately above the very small grayish white triangle on the lower edge.

The material in the dark area, according to Rogers, is coated with a gum that contained both dyes and mordants (a reagent that fixes dyes to textiles). This is uncharacteristic of the rest of the Shroud. The thread in the dark area also shows different bleaching techniques from those used on the rest of the cloth as evidenced by different amounts of lignin (a complex polymer; a non-carbohydrate constituent of wood and flax). Microchemical tests also reveal vanillin (C8H8O3), a component of lignin that decreases over time. It has essentially disappeared from the main cloth of the Shroud (as it has on the Dead Sea Scroll wrappings). Rogers summarizes plainly and precisely: “The radiocarbon area is outstandingly different from the rest of the cloth.”

The presence of gum Arabic, the evidence of new thread, vanillin, and the definitive UV-fluorescence photograph is certainly enough to credibly challenge the date established by the Carbon 14 tests. There is no way to check carbon 14 test because this method of testing destroys the samples. It is also unlikely—and reasonable—to doubt that the Vatican would allow new carbon 14 tests unless a clear, failsafe, and non-controversial testing protocol can be established. That is unlikely in the foreseeable future. But the clear evidence of substantial contamination is enough to call the carbon 14 results into question. They can no longer be thought of as definitive.

In another independent study, newer thread has been identified by several textile experts; enough newer thread to allow Beta Analytic, the world’s largest and probably most prestigious radiocarbon dating firm, to estimate that the true date of the cloth’s origin is much older—within a statistically acceptable margin of error. Beta Analytic estimates that it is possible the Shroud originated in the first century by calculating that a mixture of 60% thread material from the 16th century with 40% thread material from the 1st century would yield the erroneous medieval date range derived by the dating labs.