Photos or it didn't happen.
The researchers used the image on the cloth to work out the mechanics of the crucifixion, such as where the nails were hammered in, according to the abstract. They tried to re-create these features when they placed each volunteer on the cross. The male subjects “were carefully chosen to correspond, as closely as possible, to the physiology depicted by the frontal and dorsal imprints visible on the Shroud of Turin,” they write in the abstract. “The cross and suspension system were designed to accommodate various positional adjustments of the body as appropriate.” Edit
Were they also carefully stripped naked and nailed in position? What kind of shoddy research was this!
There is a back story here that maybe is of some interest. The Shroud of Turin is a cloth which surfaced in Medieval times which bears an imprint of a crucified man--but it's a photographic negative. The man has his hands strategically placed to cover his penis (why not use an extra cloth for modesty, Joe of Arimathea, and you have shroud to preserve modesty anyway), and looks just like Jesus is supposed to have looked--like Cesare Borgia, according to the blog "how did Jesus get so hot?". (An English forensic anatomist proposed a very different picture of Jesus based on skeletons from the time--a short guy with dark skin and a big nose.) The cloth has scorch marks from a fire in the cathedral in which it is kept under glass. The image is highly distorted, with legs and arms clearly out of proportion with each other and with the trunk.
There is an existing letter to the Pope at the time, which says that "the cloth is a forgery, and I know the artist".
This cloth was suddenly "discovered" by religious types and offered as proof of the resurrection. The archbishop allowed samples to be taken (avoiding the scorched areas). "Porphyrins" were found by a (mostly) evangelical scientific team, among whose members was this physicist Jackson. They claimed this was evidence of blood. Pollen grains from the Middle East were found on the cloth. Jackson apparently is still at what he did then. He employed lasers and other sophisticated high tech on real people to "prove" that the distorted image could have been caused by "cloth drape". He also claimed there was evidence that the image was caused by an "intense" energy field--probably "dazzling light".
The non-evangelical member of the team pointed out the presence of red ochre and other pigments. Iron could have come from pigments. Porphyrins are present in plants (chlorophyll, for example), not just heme in blood. Pollen blows around a lot, and can be found in Antarctica. So, three of the samples were carbon-dated. All showed a Medieval date. The samples dated at the University of Arizona in Tucson and in Zurich agreed within experimental error. The one from Oxford (if I recall--maybe Cambridge) was earlier and was an outlier, but still 12th century. A statistical analysis using a "chi-squared test" (which computes the probability that different results came from a common sample) showed it was improbable that the Oxford result came from the same sample. The results were published in the peer-reviewed journal Science (it was a formal paper, but the journal also has a news section, to which this link years later refers.)
People also replicated the "photographic negative" by carving a statue in wood and draping a pigmented cloth over it ("The Skeptical Enquirer" got the effect using a cheap souvenir punch out of Bing Crosby's face--basically a Halloween mask).
Statistics texts will tell you that chi-squared is not really valid with only three data points (you can derive examples), and a statistician on the Oxford team attributed the result to "bad luck" (mathematically speaking).
But the "Shroud Science" proponents seized on the discrepancy to claim that the Oxford team was engaged in fraud. They claimed the letter to the Pope (which physically exists) was "never sent". They pointed to the "mysterious" chemistry that indicates "high energy" (if you are going to reanimate a body, it isn't clear why you'd need "intense energy" to do it--if you're a magic guy like God you could even use a Star Trek "transporter" and "beam Him up, Scotty").
Almost everyone accepts that the Shroud is a Medieval forgery (or objet d'art, if you prefer), but Jackson apparently never has.
This story is informative. Experimental results in complex cases (like climate change) always have enough wiggle room so that people can cast doubt on clear evidence, even if they themselves have nothing definitive to back up their alternative explanations.
(The models in the "cloth drape" experiment wore loin clothes, by the way--they're evangelicals, after all.)
