http://www.innoval.com/C14/
and to summerise:
Radiocarbon Dating Red Flags
There were other clues, as well. All of them were warning signs that something might be wrong with the carbon 14 samples:
Giovanni Riggi, the person who actually cut the carbon 14 sample from the Shroud stated, "I was authorized to cut approximately 8 square centimetres of cloth from the Shroud…This was then reduced to about 7 cm because fibres of other origins had become mixed up with the original fabric …" (emphasis mine)
Giorgio Tessiore, who documented the sampling, wrote: “…1 cm of the new sample had to be discarded because of the presence of different color threads.” (emphasis mine)
Edward (Teddy) Hall, head of the Oxford radiocarbon dating laboratory, had noticed fibers that looked out of place. A laboratory in Derbyshire concluded that the rogue fibers were cotton of “a fine, dark yellow strand.” Derbyshire's Peter South wrote: “It may have been used for repairs at some time in the past…”
Gilbert Raes, when later he examined some of the carbon 14 samples, noticed that cotton fibers were contained inside the threads, which could help to explain differences in fiber diameter. This may also explain why the carbon 14 samples apparently weighed much more than was as expected.
Alan Adler at Western Connecticut State University found large amounts of aluminum in yarn segments from the radiocarbon sample, up to 2%, by energy-dispersive x-ray analysis. Why aluminum? That was an important question because it is not found elsewhere on the Shroud.
The radiocarbon lab at the University of Arizona conducted eight tests. But there was a wide variance in the computed dates and so the team in Arizona combined results to produce four results thus eliminating the more outlying dates (reportedly they did so at the request of the British Museum, which was overseeing the tests). Even then, according to Remi Van Haelst, a retired industrial chemist in Belgium, the results failed to meet minimum statistical standards (chi-squared tests). Why the wide variance in the dates? Was it because of testing errors? Or was it because the sample was not sufficiently homogeneous? The latter seems very likely now, and the statistical anomaly indicates something very suspicious about the samples.
Bryan Walsh, a statistician, examined Van Haelst’s analysis and further studied the measurements. He concluded that the divided samples used in multiple tests contained different levels of the C14 isotope. The overall cut sample was non-homogeneous and thus of questionable validity. Walsh found a significant relationship between the measured age of various sub-samples and their distance from the edge of the cloth. Though Walsh did not suggest invisible reweaving, it is consistent with his findings.
