As reported in Nature, Professor Bray of the Instituto di Metrologia 'G.

Colonetti', Turin, "confirmed that the results of the three laboratories were mutually compatible, and that, on the evidence submitted, none of the mean results was questionable." Although the quality of the radiocarbon testing itself is unquestioned, criticisms have been raised regarding the choice of the sample taken for testing, with suggestions that the sample may represent a medieval repair fragment rather than the image-bearing cloth.

arizona dating  room-14

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.

The remaining sample, measuring 81 mm × 16 mm (3.19 in × 0.63 in) and weighing 300 mg, was first divided in two equal parts, one of which was preserved in a sealed container, in the custody of the Vatican, in case of future need.

The other half was cut into three segments, and packaged for the labs in a separate room by Dr Tite and the archbishop.

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.

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.

The actual provenance of these threads is uncertain, as Gonella was not authorized to take or retain genuine shroud material, Raymond Rogers stated in a 2005 article that he performed chemical analyses on these undocumented threads, and compared them to the undocumented Raes threads as well as the samples he had kept from his STURP work.