Cloudy shroud
Is the linen a holy relic or just a pious fraud?

BY JEFFERY L. SHELER

The mystery of the Shroud of Turin appeared solved in the 1980s. Radiocarbon dating and other scientific tests seemed to expose the famous yellow linen as a medieval forgery. The cloth, scientists said, was a product of the Middle Ages. The faint, blood-stained image of a bearded man, bearing wounds consistent with the biblical account of Jesus's crucifixion, was not a photographic image somehow burned into the fabric at the moment of Resurrection. Rather, it was composed of red ocher and vermilion tempera paint.

Yet the debate goes on. Revisionist scholars are raising new evidence and arguments suggesting the shroud is no fake.

Last year, a botanist from Hebrew University in Jerusalem reported that his analysis of pollen grains and plant images taken from the shroud places its origin near Jerusalem before the eighth century. Prof. Avinoam Danin identified pollen and imprints of 28 species of plants native to the Jerusalem region in March and April. The flowers, he said, apparently had been placed atop the shroud. "This evidence backs up the possibility it is genuine," said Danin, "and there is no doubt that it comes from the land of Israel."

Found in France. Perhaps the most dramatic new findings relate to the accuracy of radiocarbon-dating tests conducted at three independent labs in 1988. Analyzing a small patch cut from the shroud's edge, researchers at each lab concluded that the cloth was woven between A.D. 1260 and 1390, roughly the period when the shroud surfaced in Lirey, France. At first, shroud supporters suggested that the tiny sample had been taken from a section previously damaged and rewoven and that the shroud itself was tainted with carbon residue from a 1532 fire. The scientists who conducted the tests refuted both arguments. The sample, they said, had not been cut from a damaged area. And any fire-related residue would have been removed during a cleaning process before the tests.

Leoncio Garza-Valdes, a San Antonio pediatrician, has launched a more formidable assault on the 1988 tests. He claims to have discovered microbial contamination on the shroud samples, which, he says, would have dramatically altered the radiocarbon dating. Using photomicrography, Garza-Valdes found an organic bioplastic coating–a natural funguslike growth over the cloth's fibers that would not have been removed by a standard cleaning. A similar coating, he says, has been found on other ancient textiles.

Not everyone buys Garza-Valdes's theory. Joe Nickell, senior research fellow with the Committee for the Scientific Investigation of Claims of the Paranormal and a leading shroud skeptic, argues that for there to be sufficient contamination to make the shroud 2,000 years old instead of a mere 700, "there would have to be twice as much [bioplastic] debris, by weight, as the entire shroud itself!"

But Harry E. Gove, a nuclear physicist at the University of Rochester who designed the carbon-dating technique used on the shroud, thinks Garza-Valdes may be on to something. "There is a bioplastic coating on some threads, maybe most," says Gove. If present in sufficient quantity, it "would make the fabric sample seem younger than it should be" in a carbon-dating test.

After a public showing of the shroud this summer, church officials may allow new scientific tests. "The last word has not yet been said," says Archbishop Severino Poletto of Turin, Italy, the shroud's custodian. Yet even if the shroud should be found to date from the first century, it would not necessarily make it the burial cloth of Jesus. As one shroud researcher has said, "There's no lab test for Christ-ness."