UV Fluorescence Imagery of the Turin Shroud – Digitally Revisited

UV fluorescence imagery of faint or fragile images and markings (writing) on relics and artwork is an affordable non-destructive tool useful in revealing often invisible details and in monitoring temporal stability. UV fluorescent images of Turin were recorded for the first time during the 1978 scientific investigation. The original images were recorded on color film and now have been digitally scanned and enhanced using image processing software. The processed UV images contain spectral discriminatory information and high spatial detail resolution with high contrast that is not discernable in white light images. Differing fluorescent emission colors were found to be associated with image features such as body image, burns, blood flows, skin wounds and water flows on the Turin Shroud. Spectral signature information has the potential for assisting the determination or elimination of the causes responsible for the appearance of the various features. Inconsistent and non-uniform exposure problems in the original photography were revealed, and their impact the subsequent digitization of the images is discussed. Suggestions for future fluorescence image collection include the design of equipment that will eliminate the problems associated illumination and film exposure. The extraction of spectral and spatial detail through UV fluorescence imagery is relevant to tracking temporal and climatic changes to assist conservation efforts.