Only Zurich, Oxford and Arizona were given sampling. The archaeologists and the Vatican scientists were snubbed. What would they add? Balance. Archaeologists estimate dates with an extra dimension of historical context, as carbon dating is often inexact. The Vatican scientists can be reassured that the 14C carbon dating laboratories have produced reliable figures, if they get to test the same samples themselves, as the religious POV.
Accelerator Mass Spectroscopy for radiocarbon dating was a new technique and few laboratories had the facilities. The original proposal (from scientists BTW) was to use seven labs and two different techniques for radiocarbon analysis, plus numerous other tests. However the Vatican and STURP prevented this programme.
Hence three labs and an exemplary example of
14C dating show that, in agreement with the other evidence, the shroud was a medieval fake.
To summarise:
Fact 1: Three independent laboratories used a reputable carbon dating method on an agreed portion of this piece of cloth. They also tested some controls.
Fact 2: All three laboratories dated the cloth within a range of between the mid 13th century to the late 14th century.
Fact 3: One of the laboratories introduced a blinding stage, to ensure that nobody could accuse them of bias, error or collusion.
Fact 4: All the laboratories sub-divided their supplied samples and applied different techniques to remove contamination.
Fact 5: The textile experts who studied the sampled area agreed that it was free from scorching, repair or patching.
Fact 6: The micro-photographs taken by STURP show the linen banding proceeding uninterrupted through the sampled area. This banding is invisible to the naked eye. There is no patch.
Fact 7: To produce the achieved result in error from an actual first century CE cloth a huge amount of modern material would have be needed to be mixed with the cloth. This would be obvious to those who studied the cloth.
And finally: the shroud is a medieval fake. This has been well established by scientific testing (chemical, microscopic, spectroscopic and radioisotopic), expert examination (textile, weave and artistic style) and historical research (comparison to others, culture and documentation) and is supported by other evidence:
Historical: the lack of evidence for the shroud's existence prior to the mid fourteenth century; further it's emergence during the 'holy relic' craze (along with about forty other such burial shrouds); lack of mention of a miraculously imaged Shroud in any early Christian writings; the distinct changes in the shroud, fading of colour, since its first exposure.
Physiological: the lack of resemblance of the shroud image to an actual human body; likewise the position of the body with hands folded across the genitals isn't possible for a body lying flay (the arms aren't long enough).
Textile: the weave patten of the shroud does not match anything known from first century Mid East but matches medieval Europe well; no example of the complex herringbone twill weave has even been shown to come from the first century Mid East.
Testimony: the d'Arcis Memo indicates the shroud was created around 1354 and was a known fake not many year later.
Artistic: the face of the image resembles medieval Byzantine style, with Gothic elements; the unnaturally elongated body shape and extremities are typical of the elongated style the Late Medieval/High Gothic period.
Reproducibility: contrary to the claims of shroudies the image can and has been reproduced using medieval methods.
Analytic: examination, microscopic (including electron microscopy) and chemical testing show the shroud image is made from common artistic pigments of the period of its origin.
Cultural: the shroud does not match with what is known of first century Jewish burial practices (including the only actual sample of such cloths) or the only extant sample of such burial cloths; nor does the shroud match the biblical accounts; nor are there any demonstrated artifacts of the putative Jesus extant today; nor does the supposed historical background indicate that such a cloth would have been preserved, certainly without much publicity prior to ~1355.
Serological: a minor point (as blood probably wouldn't survive this long anyway) but despite the best attempts of (and much lying and pseudoscience by) shroudies there is no evidence for blood residue.
Frankly the
consensus of all the factors is the strongest reason to accept the medieval origin of the shroud, not any one factor.
S/he can do his/her own research.
