Visibility of the Shroud Image: An Optical Physicist�s Perspective by John Dee German (deegerman@comcast.net). Friday, August 15, 10:45 a.m.�11:00 a.m. 

During the 1978 STURP tests on the Shroud of Turin, the author observed an interesting phenomenon: the contrast between the image and the non-image areas of the cloth appears to increase as the distance between the Shroud and the observer (or camera) increases. At very close distances, much of the image is barely perceptible. However, at longer distances, the image becomes more perceptible and the level of discernible detail increases. At close distances, much of the image is barely perceptible. However, at longer distances, the image in general appears darker than the surrounding native cloth and the relative shade difference between the more intense image areas; such as the nose, cheeks, pectorals and knees; and the lighter portions of the image increases. The author, being an optical physicist, formed a hypothesis for the cause of this counter-intuitive phenomenon (longer distance produces increasing perception of detail) based on varying diffusivity of light reflections from the cloth. In this paper, support for the hypothesis is developed analytically and demonstrated with experimental results. Conclusions include a discussion of the implications of these results to other areas of Shroud research.