The heated debate still rages as to how the seemingly miraculous, life-size, two-fold image of the crucified Christ appeared on the Shroud of Turin. Was it the actual burial cloth which wrapped Christ's body 2000 years ago or was it simply a clever medieval forgery? Prof Nicholas Allen, the originator of the photographic hypothesis for image formation on the Shroud of Turin, has been researching this phenomenon since 1988. He shares the secrets of how medieval alchemists managed to make this incredible image over 600 years ago and successfully addresses, inter alia, the following issues: The historical evidence for persons knowing about the camera obscura, lenses and light-sensitive chemicals before c. 1357. He also shares with you his exhaustive, practical experimentation in order to ascertain the possibility of producing an image which duplicates the characteristics of the Shroud of Turin employing only those substances and equipment that existed in a medieval society.