The main part of the shroud does not contain these materials." He speculated that these products may have been used by medieval weavers to match the colour of the original weave when performing repairs and backing the shroud for additional protection.
Based on this comparison Rogers concluded that the undocumented threads received from Gonella did not match the main body of the shroud, and that in his opinion: "The worst possible sample for carbon dating was taken." As part of the testing process in 1988, Derbyshire laboratory in the UK assisted the Oxford University radiocarbon acceleration unit by identifying foreign material removed from the samples before they were processed.
It is hypothesised that the sampled area was a medieval repair which was conducted by "invisible reweaving".
Since the C14 dating at least four articles have been published in scholarly sources contending that the samples used for the dating test may not have been representative of the whole shroud.
In 1988, scientists at three separate laboratories dated samples from the Shroud to a range of 1260–1390 CE, which coincides with the first certain appearance of the shroud in the 1350s and is much later than the burial of Jesus in 30 or 33 CE. Samples were taken on April 21, 1988, in the Cathedral by Franco Testore, an expert on weaves and fabrics, and by Giovanni Riggi, a representative of the maker of bio-equipment "Numana".The lab representatives were not present at this packaging process, in accordance with the protocol.The labs were also each given three control samples (one more than originally intended), that were: and communicated their results to the British Museum. that radiocarbon measurements on the shroud should be performed blind seem to the author to be lacking in merit; … group and the candidate laboratories turned into a P. However, in a 1990 paper Gove conceded that the "arguments often raised, …