Role of calcium carbonate in fibre discoloration on the Shroud of Turin

摘要

Introduction: The Shroud of Turin, a linen cloth bearing the faint, yellowed image of an apparently-crucified man, is the most intensely studied artifact of all time. Scientific tests revealed that the image color resides on the topmost fibers at the highest parts of the weave resulting from a chemical surface change in the linen. We propose and preliminarily test a novel hypothesis that precipitated calcium carbonate crystal, originating from a natural fabric washing process, played a significant role in the starch surface discoloration. Methods and materials: Modern, dye-free linen was supersaturated in hard tap water with mild acetic acid and air dried. Resulting discolored fibers were scientifically evaluated in comparison to pristine fibers and Shroud image fibers. Results: Evaluations using scanning electron microscope, Micro- Attenuated Total Internal Reflectance Fourier-transform infrared analysis (ATR-FTIR), secondary ion mass spectrometry, chemical analyses, and microscopic comparative analyses all revealed nearly identical findings as those found on Shroud image fibers. Discussion: To date, all Shroud image-formation hypotheses have failed when compared with known data. We present preliminary experimental data supporting the novel hypothesis that precipitated calcium carbonate played a significant role in differentially discoloring the surface fibers in the image region of the Shroud. Our hypothesis may also explain the Shroud image intensity as related to cloth-body distance studies. Conclusion: Although the results of this study are compelling, several other experiments need to be conducted including those that incorporate the parameters occurring in a Jerusalem tomb microenvironment. The success of this hypothesis does not speak to the issue of whose body was wrapped in the Shroud or the time period of image formation.