<P> In 2009, Luigi Garlaschelli, professor of organic chemistry at the University of Pavia, announced that he had made a full size reproduction of the Shroud of Turin using only medieval technologies . Garlaschelli placed a linen sheet over a volunteer and then rubbed it with an acidic pigment . The shroud was then aged in an oven before being washed to remove the pigment . He then added blood stains, scorches and water stains to replicate the original . But according to Giulio Fanti, professor of mechanical and thermic measurements at the University of Padua, "the technique itself seems unable to produce an image having the most critical Turin Shroud image characteristics". </P> <P> Garlaschelli's reproduction was featured in a 2010 National Geographic documentary . The technique used by Garlaschelli included the bas relief approach (described below) but only for the image of the face . The resultant image was visibly similar to the Turin Shroud, though lacking the uniformity and detail of the original . </P> <P> According to the art historian Nicholas Allen, the image on the shroud was formed by a photographic technique in the 13th century . Allen maintains that techniques already available before the 14th century--e.g., as described in the Book of Optics, which was at just that time translated from Arabic to Latin--were sufficient to produce primitive photographs, and that people familiar with these techniques would have been able to produce an image as found on the shroud . To demonstrate this, he successfully produced photographic images similar to the shroud using only techniques and materials available at the time the shroud was supposedly made . He described his results in his PhD thesis, in papers published in several science journals, and in a book . Silver bromide is believed by some to have been used for making the Shroud of Turin as it is widely used in photographic films . </P> <P> Scientists Emily Craig and Randall Bresee have attempted to recreate the likenesses of the shroud through the dust - transfer technique, which could have been done by medieval arts . They first did a carbon - dust drawing of a Jesus - like face (using collagen dust) on a newsprint made from wood pulp (which is similar to 13th - and 14th - century paper). They next placed the drawing on a table and covered it with a piece of linen . They then pressed the linen against the newsprint by firmly rubbing with the flat side of a wooden spoon . By doing this they managed to create a reddish - brown image with a lifelike positive likeness of a person, a three - dimensional image and no sign of brush strokes . However, according to Fanti and Moroni, this does not reproduce many special features of the Shroud at microscopic level . </P>

When was the shroud of turin last displayed