International Journal of Archaeology

Submit a Manuscript

Publishing with us to make your research visible to the widest possible audience.

Propose a Special Issue

Building a community of authors and readers to discuss the latest research and develop new ideas.

Analysis of Photoelectric Colorimetry and Fluorimetry of the Turin Shroud

We analyze spectrophotometric data collected directly on the Turin Shroud in 1978. Using standard methodologies, we transform 19 visual reflectance and 16 UV-fluorescent emission spectra to CIE xyY color space coordinates. We then compare these results to those of an Italian team of investigators. Comparing x-y chromaticities, the reflectivities from clear areas (background), image, and blood-stain locations agree with corresponding data collected independently by the Italian team. In both sets of data, the clusters from image and background areas overlap strongly and are clearly separated from the blood-stain points. Data from lightly scorched areas fall within the clusters from background and image locations. Data from deeper scorches diverge significantly, as do all scorch data from the Italian team. We generate similar colorimetric data from the spectral UV-fluorescence measurements made by the Shroud of Turin Research Project (STURP). Plotted as x-y chromaticities, the clear areas group together as a cluster as do the blood data but the two clusters show a significant separation from each other. The scorch data are configured along a linear continuum advancing from the lightest clear areas to the darkest scorches. The image data bifurcate: two of the four points lie within the clear-area cluster and the two outliers fall in line with the scorch data. We offer interpretations and speculations on these findings. Quantification of the 1978 measurements establishes a procedure for future monitoring of the aging state of TS features. The measurement protocol and methodologies discussed are important for preservation of other historical art and historical relics.

Photoelectric Colorimetry, UV Fluorescence, Turin Shroud, Relic Conservation

APA Style

Larry Schwalbe, Samuel Pellicori. (2023). Analysis of Photoelectric Colorimetry and Fluorimetry of the Turin Shroud. International Journal of Archaeology, 11(1), 1-8.

ACS Style

Larry Schwalbe; Samuel Pellicori. Analysis of Photoelectric Colorimetry and Fluorimetry of the Turin Shroud. Int. J. Archaeol. 2023, 11(1), 1-8. doi: 10.11648/j.ija.20231101.11

AMA Style

Larry Schwalbe, Samuel Pellicori. Analysis of Photoelectric Colorimetry and Fluorimetry of the Turin Shroud. Int J Archaeol. 2023;11(1):1-8. doi: 10.11648/j.ija.20231101.11

Copyright © 2023 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License ( which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. Jumper, E. J., Adler A. D., Jackson J. P., Pellicori S. F., Heller J. H., and Drusik J. R., "A Comprehensive Examination of the Various Stains and Images on the Shroud of Turin,” Archaeological Chemistry III, ACS Advances in Chemistry No. 205, J. B. Lambert, Editor, Chapter 22, American Chemical Society, Washington D. C., 1984, pp. 447-476.
2. Commission Internationale de l'Éclairage (CIE). Publication No. 15, Colorimetry, 1986, 1971. (CIE 1986).
3. Commission Internationale de l'Éclairage (CIE). “Standard on Colorimetric Observers,” CIE S002, (1986).
4. Freebody, M., “More than Skin Deep: Photonics Protects our Cultural Heritage,” (2022).
5. Gilbert, Jr, R., and Gilbert, M., “Ultraviolet-Visible Reflectance and Fluorescence Spectra of the Shroud of Turin,” Applied Optics 19, pp. 1930-1936 (1980).
6. Pellicori, S. F., and Chandos, R. A., “Portable Unit Permits UV/vis Study of the ‘Shroud’” reprinted from Industrial Research & Development – February 1981.
7. Soardo P., Iacomussi P., and Rossi G., “Colourimetry of the Shroud” in “The Shroud, past, present and future,” International Scientific Symposium, Torino, 2-5 March 2000 – Effatá Editrice, Cantalupa (TO) pp. 89-100 (2000).
8. Pellicori, S. F., “Spectral Properties of the Shroud,” Applied Optics 19 (12), pp. 1913-1920 (1980).
9. Privitera, C., “Digital Colorimetric Analysis of the Shroud of Turin,” MATEC Web of Conferences 36, DOI 1051/matecconf/20153602002 (2015).
10. Devan, D. and Miller, V., "Quantitative Photography of the Shroud of Turin," IEEE 1982 Proceedings of the International Conference on Cybernetics and Society, pp. 548-553, (October 1982).
11. Miller, V. D. and Pellicori, S. F., "Ultraviolet Fluorescence Photography of the Shroud of Turin," Journal of Biological Photography 49 (3), pp. 71-85, (1981).
12. Pellicori, S., and Evans M. S., “The Shroud of Turin Through the Microscope,” Archaeology, pp. 34-43, (January/February 1981).
13. ©1978 Barrie M. Schwortz Collection, STERA, Inc.
14. Walker, J., “Color Rendering of Spectra,” /specrend/ (1996).
15. Lindbloom, Bruce J., “Chromatic Adaptation,” (revised 2017).
16. Schwalbe, L. A., and Rogers, R. N., “Physics and Chemistry of the Shroud of Turin,” Analytica Chimica Acta 135, pp. 3-49, (1982).
17. Samuel Pellicori, “UV Fluorescence Imagery of the Turin Shroud – Digitally Revisited” International Journal of Archeology, Vol 8, No. 2, 32-36 (2020) doi 10.11648/j.ija 20200802.13.