The Arizona group split each sample into four subsamples.
Photography of the shroud by Secondo Pia in 1898 indicated that the image resembled a photographic 'negative' and represents the first modern study.
Subsequently the shroud was made available for scientific examination, first in 19 by a committee appointed by Cardinal Michele Pellegrino .
All laboratories examined the textile samples microscopically to identify and remove any foreign material.
The Oxford group cleaned the samples using a vacuum pipette, followed by cleaning in petroleum ether (40° C for 1 h) to remove lipids and candlewax, for example.
Each subsample was treated with 1M HCL (80° C for 2h), 1M Na OH (80° C for 2 h) and again in acid, with rinsing in between.
Two of the three samples were then bleached in Na OCL (2.5% at p H-3 for 30 min).
The three control samples, the approximate ages of which were made known to the laboratories, are listed below. T/32) from a tomb excavated at Qasr Ibrîm in Nubia by Professor J. This linen was dated in the British Museum Research Laboratory using liquid scintillation counting, giving a radiocarbon age of 2,010 ± 80 yr BP (BM-2558).
Two were in the form of whole pieces of cloth (samples 2 and 3) and one was in the form of threads (sample 4). This corresponds to a calendar age, rounded to the nearest 5 years, of 110 cal BC - AD 75 cal at the 68 per cent confidence level (where cal denotes calibrated radiocarbon dates). Threads removed from the cope of St Louis d'Anjou which is held in a chapel in the Basilica of Saint-Maximin, Var, France.
Among those present when the sample as cut from the shroud were Cardinal Anastasio Ballestrero (Archbishop of Turin), Professor L. The laboratories were not told which container held the shroud sample.