Textile Evidence Supports Skewed Radiocarbon Date of Shroud of Turin
M. Sue Benford and Joseph G. Marino
©2002 All Rights Reserved
ABSTRACT
The most studied artifact in human history is the Shroud of Turin, a 14 by 3.5 foot sheet
of linen with lightly-shaded ventral and dorsal images of an apparently crucified man
matching the wounds reported to have been incurred by Jesus of Nazareth. In 1988,
Carbon-14 (C-14) dating of a corner section of the cloth produced dates ranging from
1260 to 1390 A.D.(1) This paper presents new evidence demonstrating that it is highly
probable that the C-14 samples were not characteristic of the main Shroud and were
spurious.
Introduction
On August 28, 2000, at the Worldwide Congress "Sindone 2000" in Orvieto,
Italy, the paper entitled, "Evidence for the Skewing of the C-14 Dating of the Shroud of
Turin Due to Repairs" was originally presented. (2) This paper proposed a hypothesis that
a âpatchâ of material, from the 16th Century, was skillfully spliced into the 1st Century
original Shroud cloth in the C-14 sample used by the laboratories for testing; thus,
altering the date to make it appear more modern than the main Shroud. Several
supporting arguments were provided in this paper. Among these arguments included
calculations performed by Beta Analytic, the worldâs largest radiocarbon dating service,
that the observed proportion of medieval material in relationship to assumed 1st Century
material, matches the findings of the AMS Labs in 1988. Second, the paper reported the
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results of three blinded reviews of photographs of the uncut C-14 sample, and one of the
sub samples, by independent textile experts. All of the experts reported seeing what
appeared to be aberrant weaving on one side of the sample. Third, the paper proffered an
historical interpretation of why the area had been patched in the 16
th
Century. Finally, a
review of the statistical analysis of the dates obtained by each of the three AMS Labs, as
they relate to the sampleâs distance to the edge of the cloth, was shown to produce a
nearly identical angle as the observable angle delineating the two disparate weave
patterns in the C-14 sample.
This paper was critiqued by many of the world-renowned radiocarbon experts
involved in the 1988 dating of the Shroud. Included in the review process were: Dr.
Timothy Jull, Editor of the journal Radiocarbon; Harry Gove, IsoTrace Laboratory,
Department of Physics, University of Toronto; Paul E. Damon, University of Arizona
radiocarbon laboratory; Jacques Evin, Centre de Datation par le Radiocarbone; Gabriel
Vial, Professor at Institut des Textiles de Lyon; Prof. Franco A. Testore, Torino, Italy;
textile expert Mechtild Fluery-Lemberg; archaeologists, William Meacham and Paul
Maloney (3); and former STURP member and chemist Dr. Ray Rogers (4, 5). Dr. Rogers
has in his possession both main Shroud and Raes sample threads, which enabled him to
test the hypothesis posited in the paper.
The purpose of this paper is to: 1) address the concerns raised by the above
referenced reviewers; and 2) to provide new evidence garnered since the paperâs original
presentation supporting the 16th Century âpatchâ hypothesis. Extensive and compelling
data are now available to successfully demonstrate that an incorrect medieval dating
conclusion was made concerning the Shroud of Turin.
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Concerns raised by reviewers
In providing a summation of reviewersâ comments, Dr. Jull offered the following:
â1. The paper asserts that the dates for the sample can be explained by a section of cloth
sewn into an adjacent (older) cloth. It is stated this addition is invisible. The authors
assert this can explain the differences in ages between the 3 radiocarbon labs, which
dated the Shroud. This assumes several things, including that the radiocarbon labs
homogenized the entire sample they received. Further, Gove indicates the calculation
given by Mr. Hatfield is incorrect and in any case, this calculation is based on an
unprovable hypothesis.
2.
Several reviewers (Damon, Evin, Testore, Vial) state that the added piece of cloth on
one side of the Shroud was clearly visible and avoided. This is stated most clearly by
Testore, who writes, âthe carbon samples represented the bulk of the Shroud and the
hypothesis based on the influence of repairs on the datation has no fundament [sic] . . .â
3.
The paper does not appear to add anything new to the scientific discussion of the
Shroud. Several reviewers suggest it only causes confusion by adding âsubjectiveâ
material and assumptions not based on direct or indirect measurements, or demonstrable
historical evidence.
4.
Several reviewers argue that
Radiocarbon
is an inappropriate place for a speculative
article about dating of the Shroud.
5.
From my own perspective, I would remind you that your hypothesis requires that the
samples in each lab were combined together, whereas I know that in our lab at least, the
samples were cut into smaller fragments, which were dated independently. I think this
was also done at Zurich. I am not sure what was done at Oxford.â
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In his individual review, Gove asserts, âA mixture of 60% 1500 AD cloth and 40%
75 AD cloth by mass gives a date of 665 AD, not 1210 AD as claimed by Beta Analytic.â
(Gove). Further, Vial and Testore declare, âWe carefully inspected the shroud and we are
sure that this sampling place was representing the whole shroud.â (Vial) âI examined
carefully the cloth all along the warp and filling of the threads concerned, without
noticing any splicing.â (Testore)
In addition to the summary comments provided by Jull, another concern raised by
Damon, and expressed by other independent reviewers (Fluery-Lemberg, Meacham,
Maloney), was the credibility of the claim that 16
th
Century European weavers could
repair a textile with an âinvisibleâ patch. This concern also needs to be satisfactorily
addressed.
Response to Concerns
Calculation by Beta Analytic
:
Three main lines of supporting data demonstrate the veracity of the hypothesis
that approximately 60% of the C-14 sample represented 1500 AD threads while
approximately 40% represented 1
st
Century threads, thus resulting in C-14 dates between
1260 â 1390 AD. First, the percentage of aberrant (patch) threads was selected based
upon visual examination of a C-14 sample and sub sample photograph by three
independent and blinded textile experts. Second, the percent calculation was obtained
using the estimates of these textile experts. Third, the radiocarbon date was calculated
using the percentage of observed 16
th
Century versus 1
st
Century weave types appearing
in the sample.
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The radiocarbon calculations were derived using the following mathematical
calculations and in consideration of the following scenarios. âScenario Aâ represents the
authorsâ original proposal while âScenario Bâ represents the counter-claim asserted by
Dr. Gove.
Scenario A. What % cal AD 1500 + % cal AD 75 radiocarbon would be required to
derive an average age of cal AD 1210?
Scenario B. What % cal AD 1500 + % cal AD 75 radiocarbon would be required to
derive an average age of cal AD 665?
The calculation of this would be as follows:
1) The measured Conventional BP equivalent to cal AD 1500 is ~ 360 BP.
The measured Conventional BP equivalent to cal AD 75 is ~ 1940 BP.
The measured Conventional BP equivalent to cal AD 1210 is ~ 840 BP.
The measured Conventional BP equivalent to cal AD 665 is ~ 1340 BP.
Comment: "Measured Conventional BP equivalent" refers to the radiocarbon age that
would be the mean 13C/12C corrected radiocarbon age measured by the laboratory.
2). The BP dates must be converted to a fraction modern value to calculate a percent
concentration:
360 BP = 0.9558 (cal AD 1500 equivalent)
1940 BP = 0.7851 (cal AD 75 equivalent)
840 BP = 0.9003 (cal AD 1210 equivalent)
1340 BP = 0.8460 (cal AD 1210 equivalent)
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Comment: Given only two components, a linear relationship applies to the calculation
(i.e., 50/50, 25/75, 10/90 derives a straight-line relationship). The ages can not be used
because they follow a logarithmic relationship.
3). The formulas for calculation then become:
A. 0.9003 = (x)(0.9558) + (1-x)(0.7851)
B. 0.8460 = (x)(0.9558) + (1-x)(0.7851)
4). Solving for X (where X ~ % cal AD 1500 carbon present)
A. X = 0.6749 ~ 67%
B. X = 0.3567 ~ 36%
Therefore, as proposed in Scenario A, a sample containing ~ 67% cal AD 1500
radiocarbon and ~ 33% cal AD 75 radiocarbon should yield a calibrated date of ~ cal AD
1210. NOTE: the percent variability between these percentages and the original claim of
60/40 is within an accepted margin of 10%.
In contrast, according to Scenario B, a sample containing ~ 36% cal AD 1500
radiocarbon and ~ 64% cal AD 75 radiocarbon should yield a calibrated date of ~ cal AD
665. As Scenario B demonstrates, it appears as if Dr. Gove reversed the percentages of
hypothesized 16
th
Century and 1
st
Century threads in order to obtain his 665 AD dating
(calculations provided by Darden Hood of Beta Analytic, June 11, 2002).
Main Shroud deemed identical to Carbon-14 sample area
:
Although the reviewers, including Evin, remarked that the main Shroud was identical
to the C-14 sample area, Evinâs own observations call this into question. During the
audiotaped Question & Answer session at the 1989 Paris Conference (Sept. 7, 1989),
Evin responded, âI quite agree that the Labs did not take the weaving techniques into
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account and they did not date the threads per se. . . Thus, if the weave was rewoven with
threads from modern restoration, this would be reflected in more modern results.â
A comprehensive test of the âpatchâ hypothesis was conducted by former STURP
chemist Dr. Ray Rogers to ascertain whether or not a significant difference existed
between the threads found on the main Shroud and those in the Raes sample, which was
adjacent to the 1988 C-14 sample area. A detailed report of Rogersâ observations can be
www.shroud.com/pdfs/rogers2.pdf
Figure 1:
100X photomicrograph taken by STURP chemist
Dr. Ray Rogers demonstrating a splice in one of the threads
from the Raes sample adjacent to the C-14 sample.
Rogers succinctly summarized his preliminary analysis in the November
2001 (No. 54) issue of the British Society of the Turin Shroud (BSTS) Newsletter stating,
âI believe it is quite clear that the material of the Shroud is significantly different from
both the Holland cloth and the Raes sample from 1973. The samples used for the datingâ
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of 1988 were cut from immediately above the Raes sample.
It is very unfortunate that
the
14
C samples were not better characterized, because the evidence shows that it is
highly probable that the samples were not characteristic of the Shroud and were
spurious
.â (6)
No splicing was observed in the Carbon-14 sample area
:
While reviewing one of the threads from the Raes sample (Figure 17 in the above
referenced Rogersâ report), Rogers observed what appeared to be an overlap in the
middle of the thread. A 100X close up of the âspliceâ from within the Raes sample was
taken using oblique light (see Figure 1 above). Cotton was also detected in this thread.
According to the designated patch areas indicated in our original paper, the Raes
sample lines up directly with what, quite possibly, is predominantly 16
th
Century patch.
This hypothesis is also suggested by the results obtained by Rogersâ microscopic
analysis.
Possibility of âinvisibleâ repairs by 16
th
Century weavers
:
"Invisible weaving" was a popular trade in Europe during the Middle Ages. This
may be due to the fact that fabric was much more precious and "non disposable" in this
time period compared to today. Thus, repairs were essential. According to the
Genealogical Society records of RANKS, PROFESSIONS, OCCUPATIONS AND
TRADES in medieval England, the "FINE DRAWER" was "A person employed in
tailoring to repair tears in the cloth. Invisible mending."(7)
More information on this medieval-type patch repair can be found on current
websites that have kept the dying trade of invisible mending alive. According to one such
company's website:
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"Depending on the size and condition of the damaged area, and the fabric to be
worked on, one of the following methods is applied: FRENCH WEAVE - Also known as
the Invisible Weave, this technique is done on select fabrics with small tears, holes and
burns. Individual thread strands from hidden areas, such as a cuff or inseam, are actually
woven together by hand. This creates new fabric as it closes the hole and the repair is
virtually indistinguishable from the surrounding fabric. Some fabrics, such as gabardine,
don't always lend to completely invisible results. Anticipated results will be discussed
before attempting the weaving. INWEAVING - For larger tears, and when the French
weave is not practical. The weaver cuts a patch of hidden fabric and places it over the
damaged area, matching the fabric's pattern.
The frayed edges are then hand woven
into the material. The edges of the repair are invisible to the eye
.â(8)
In the âIn Weavingâ technique described above, it is important to note that there
is a requisite overlap and intermixing between the newer patch material and the existing
textile via the integration of frayed edges into the damaged textile and vice versa. Dr.
Jull noted a concern regarding the homogeneity of the sub samples stating that, âI would
remind you that your hypothesis requires that the samples in each lab were combined
together, whereas I know that in our lab at least, the samples were cut into smaller
fragments, which were dated independently.â The unavoidable interweaving required of
this invisible mending technique would, most assuredly, have created heterogeneity in the
C-14 sample area (see Figure 2 below). The exact ratio of patch versus original threads is
not determinable by photographic analysis alone; however, as previously discussed, a
well-supported estimate, based upon weave pattern changes, has been posited.
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Figure 2:
This color-enhanced image demonstrates the inherent intermixing of
fibers in the spliced Raes thread. Notice how the red and green merges into the
opposite side of the thread.
The possibility of an invisible patch being aptly rewoven into a linen textile in the
16
th
Century was brought to the attention of Dr. Thomas P. Campbell, Associate Curator,
European Sculpture and Decorative Arts, The Metropolitan Museum of Art. Dr.
Campbell, primary author of Tapestry in the Renaissance: Art and Magnificence (April
2002), wrote, "All of the major European courts had teams of skilled weavers and
embroiderers who were employed in the repair of high-quality textiles. For example, at
the English court there was a team attached to the Great Wardrobe, operating from the
Tower of London. Much information relating to the Great Wardrobe has been published
by Tout. I have a chapter on the activity relating to tapestry repairs in my unpublished
Ph.D. thesis on Henry VIII's tapestry collection (Courtauld Institute, London, 1999).
Much information on the repair of tapestries and textiles in the collections of the Dukes
of Burgundy is published in volumes of documents published in brief in the late
nineteenth and early twentieth century (for bibliography see entries in the Grove
11
Dictionary of Art). Similar documentation for the French royal collection has been
published by Laborde, and for the Habsburg collection by Michelant. There's a pretty
large bibliography in the catalogue for the current exhibition, Tapestry in the
Renaissance: Art and Magnificence now at the Met.. . .Identifying sixteenth century
repairs is not easy (eighteenth and nineteenth century repairs are much easier)."
When asked if he had any images of an actual invisible weave repair done in the
16th Century, Dr. Campbell responded, "No, I don't have such an image. As I said, it is
very difficult to identify such repairs. They certainly must exist -
the sixteenth century
weavers were magicians
, but I can't think of any documented examples." (9) (NOTE:
further documentation of 16
th
Century invisible weaving along with historically-
supported evidence is being provided in a subsequent paper by the authors).
Unauthorized dating of Raes thread
In 1982 an unauthorized Carbon-14 dating test was conducted on a single thread
from the Raes sample. The experimental thread was provided by Dr. Alan Adler and
given to Dr. John Heller. At the time, Adler was unaware that an agreement had been
signed by STURP members not to do further testing on Shroud samples. Heller delivered
the thread to the California Institute of Technology (CalTech) for dating by world-
renowned mineralogist Dr. George R. Rossman. Adler informed Rossman that one end
of the thread contained, what appeared to be, a âstarch contaminate.â Thus, Rossman cut
the thread in half and, using what Adler described as Fourier-transform ion cyclotron
resonance mass spectrometry (FTMS), dated each end of the thread separately.
According to the Scripps Center for Mass Spectrometry in La Jolla California, âFTMS
offers two distinct advantages, high resolution and the ability to tandem mass
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spectrometry experiments. First introduced in 1974 by Comisarow and Marshall, FTMS
is based on the principle of a charged particle orbiting in the presence of a magnetic field.
While the ions are orbiting, a radio frequency (RF) signal is used to excite them and as a
result of this radio frequency excitation, the ions produce a detectable image current on
the cell in which they are trapped. The time-dependent image current can then be Fourier-
transformed to obtain the component frequencies of the different ions, which correspond
to their m/z. Coupled to ESI and MALDI, FTMS has potential in becoming an important
research tool offering high accuracy with errors as low as ±0.001%.â (From
http://masspec.scripps.edu/information/intro/chapter3.html#3.3.5.)
ratio expert, Dr. Vernon Anderson of Case Western Reserve University (OH), âion
cyclotron could potentially identify C-14 peaks; however, to quantify it versus C
12
CO
2
is
difficult.â
Rossman found that the non-contaminated end of the thread dated to 200 AD
while the starched end dated to 1200 AD
. Although Rossman did not publish these
data, Adler had confidence in his capabilities to accurately measure the age of the sample.
Adler stated that Rossman is the âworldâs expert in it and thereâs no arguing with him . .
.if he says these are the dates he got . . .â (10) In a personal conversation with one of the
authors (Benford), Rossman confirmed that he was, indeed, the person who carried out
the 1982 C-14 testing on the Raes thread provided by Adler. (11)
If there is any validity to the Rossman C-14 tests of the Raes thread, then the
results support Rogersâ recent findings of a spliced thread in the Raes sample as well as
his observation of unilateral deposition of plant gum encrustations on only the Raes
fibers. It would further support the heterogeneity of inwoven medieval restorative
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threads into older, possibly 1
st
Century, Shroud fibers in both the Raes and the 1988
sample areas of the Shroud.
Conclusion
Although the results of Ray Rogersâ research testing the hypothesis posed in the
paper submitted to
Radiocarbon
was sent to the journal following the rejection of the
paper, no comment or reconsideration was forthcoming from the Editor. Perhaps the
reason for a lack of response has more to do with one of the reviewerâs poignant
observations. Jacques Evin wrote in his comments, âAll people involved in the sampling
and in laboratory analyses, will be very angry with these suspicions turning on so an
important mistake or a misconduct.â
References:
1. Damon, P.E. et al. Radiocarbon dating of the Shroud of Turin, Nature, vol. 337, no.
6208, 16 Feb 1989, pp. 611-15.
2. Marino, J. G., and Benford, M.S., Evidence for the Skewing of the C-14 Dating of
the Shroud of Turin Due to Repairs. Worldwide Congress "Sindone 2000" in Orvieto,
Italy, August 28, 2000 . Also available at
http://www.shroud.com/pdfs/marben.pdf
3. Unpublished written communications; on file.
4. Rogers, R.N. COMMENTS ON BENFORD-MARINO HYPOTHESIS, British
Society of the Turin Shroud (BSTS) Newsletter, November 2001 (No. 54).
5. Unpublished written communications; on file.
6. Rogers, R.N. COMMENTS ON BENFORD-MARINO HYPOTHESIS, British
Society of the Turin Shroud (BSTS) Newsletter, November 2001 (No. 54); 33.
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7.
www.gendocs.demon.co.uk/trades.html#T
8.
www.withoutatrace.com/dying_art.htm
9.
Via email May 17, 2002; on file.
10.
Audiotaped interview between Dr. Alan Adler and Mark Antonacci, December
28, 1988.
11.
Personal communication between George Rossman and M. Sue Benford, June 30,
2002.