Jesus Christ, the Man of the Shroud, and Biirubin by Carlo Goldoni. Sunday, August 17, 8:45 a.m.�9:00 a.m. (Posthumus paper) 

For a long time it has been proved that the red stains visible on the cloth of the Shroud of Turin are blood clots. Among many compounds, these clots also contain a considerable amount of bilirubin with an unusual content, perhaps of traumatic origin. This excess of bilirubin could be the cause of the carmine red color that these blood stains take under special circumstances. In the past, in order to investigate the relationship between the color of the stains and the amount of bilirubin, an experimental campaign was carried out with three sets of blood samples with increasing content of bilirubin (from 2�5 times the normal concentration): a set of the sample was kept unchanged, a second set was aged in an oven for 10 hours at a temperature of 120�C, and a third set was exposed for six hours to the ultraviolet light. Only in this last set of samples did the blood stains assume the carmine red color. Later on, on the basis of a model developed by J.B. Rinaudo, new sets of blood stains with increasing blood levels of bilirubin were irradiated with neutrons (2,59 x 1013 n/cm2). This irradiation had not altered the original brick red color of the blood stains. However, a subsequent ir�radiation in ultraviolet (A type) made the carmine red color emerge in all the samples within the short time of 30 minutes.