Three-Dimensional Characteristic of Shroud Image Left - Enrie Negative Photograph of Shroud Image Right - VP-8 conversion of image intensities to three-dimensional relief (copyright 1997, TSC)

Modern scientific interest in the Shroud can be said to have begun in 1898 when the Italian photographer, Secunda Pia, took the first photographs of the Shroud. During the normal course of making a photographic print, Pia noticed that the negative image on the Shroud looked very much like a photographic positive as can be seen in Figure 1. This discovery raised scientific eyebrows and began a continuous and growing scientific interest in the Shroud until the present day. The scientific significance of Pia's discovery is twofold. First, the shading of the Shroud body image is like a negative, where shades of light and dark are reversed from the way they normally appear in ordinary visual experience.

That is, we are used to seeing people with light highlights and dark shadows. But on the Shroud, this shading convention is reversed. The immediate question that arises from this result is how could the Shroud sensibly be the work of an artist or a craftsman. Such a person working in the Middle Ages or before would apparently have to work with an absolutely unfamiliar and unnatural shading structure before the advent of photography. The second significant aspect of Pia's discovery is that the information density (or correlation with anatomical subtleties of a human body) is exceedingly high, well surpassing that expected of normal artistic renditions of the human form. It is for this reason that the Shroud image has been compared to a photograph.

In 1931, the Shroud was again photographed by Giusseppi Enrie, another Italian photographer. These photographs showed the negative characteristic of the Shroud image as well, but with considerably more fidelity. The negative image of Enrie is shown in Figure 2 .

In 1902, the French Chemist Paul Vignon, in studying Pia's photograph, thought that the intensity of the Shroud image seemed to vary with expected cloth-body distance. That is, the closer the draping Shroud was to a presumed underlying body, the more intense was the body image. While he could not demonstrate this observation quantitatively, he nevertheless proposed that the image was due to ammonia vapors emanating from the body surface as an attempt to explain the distance correlation.

In 1974, it became possible to rigorously test Vignon's intensity versus cloth-body suggestion. Using a microdensitometer (an instrument that measures intensity of a photograph) and a reconstruction of how a cloth model of the Shroud drapes over a body, American Physicist John Jackson and colleagues were able to show that, indeed, image intensity does vary with cloth-body distance with a significant degree of correlation.

However, this correlation can be convincingly demonstrated using a special image analysis technique. The idea is to plot image intensity as corresponding levels of three-dimensional topographical relief. If the intensities of the Shroud image indeed correlate with cloth-to-body distance, then the resulting relief image should correspond to a sensible three-dimensional form of a human body (excluding the second order effect of cloth drape).

On February 19, 1976 Jackson brought a photograph of the Shroud to the image analysis laboratory of Bill Mottern. The Shroud image was viewed with a device called a VP-8 Image Analyzer, an analogue computer that converts image intensity directly to vertical relief. Astonishingly, the relief image looked quite anatomically plausible, even down to the subtle details of the face. Figure 3 shows the VP-8 relief of the full frontal body image on the Shroud along with the Enrie negative photograph from which it was derived. It is interesting to see how the intensities of various image features in the Enrie photograph (e.g. face, chest, hands, etc.) have been interpreted by the VP-8 as corresponding levels of relief. Clearly, the overall 3-D structure of the VP-8 image resembles a realistic human form.

If we now consider the facial relief image, shown in Figure 4 , we see (to within the resolution capabilities of theVP-8 system) that the entire three-dimensional facial structure of a normal human face is reproduced accurately. For example, we see that the nose is higher in elevation than the cheeks, which are both higher than the eye sockets, etc. We can also see that the relief structure of the lips is in proper three-dimensional relation to the nose and the cheeks. If we compare with Enrie's facial image, we can see precisely why the VP-8 relief has these characteristics. We see that the nose is plotted with the highest relief because it has the brightest intensity (See again Figure 4). The cheeks are less bright and, consequently, they wind up with correspondingly less topographical relief than the nose.

It is important to recognize that the VP-8 relief was generated from a SINGLE function of relief versus intensity applied uniformly across the entire Shroud image . Thus, the 3-D intensity correlation is a fundamental characteristic of the image structure on the Shroud. The three dimensional characteristic is discussed in detail by Jackson et al. (Ref 1).

The empirical fact that the Shroud frontal body image is highly correlated with cloth-body distance presents major problems for hypotheses describing the origin of the Shroud image. First, the "three-dimensional" characteristic of the image argues forcefully that it could not be the work of an artist. Controlled experiments with highly trained artists have demonstrated that the human eye-brain-coordination system is incapable of both recognizing and creating an intensity correlation to the degree found on the Shroud within the visible contrast variations observed currently in the Shroud image (Ref 1). We have investigated numerous artistic copies of the Shroud produced over the past several centuries with the VP-8 system. Without exception these relief images appear quite distorted (Ref 1). Moreover, we are unaware of any artistic examples in history where someone thought to intentionally encode the intensity structure of their artwork with three-dimensional meaning.

Accordingly, we must consider that the image on the Shroud was the result of a physical process of some sort (because the intensity-distance correlation reveals a mathematical order in the image structure). However, we can reject, on the basis of this correlation, the hypothesis that the image was the result of a direct contact transfer from a body to the cloth (because we see body image discoloration where cloth contact is extremely doubtful). We can also exclude simple diffusion or radiation from a body shape, because both transfer mechanisms, while acting through space, would produce a blurred image. This latter category, in fact, rejects Vignon's ammonia vapor diffusion hypothesis mentioned above. Details of these and other image hypotheses in light of the Shroud's three-dimensional characteristic are discussed by Jackson et al. (Ref 1).

In 1978, the Shroud was studied first-hand by a team of professional scientists from the United States, called STURP (Shroud of Turin Research Project, Inc.) This team was composed of scientists from universities, scientific laboratories, and scientific industries. STURP was allowed by the Cardinal of Turin, the custodian of the Shroud, to acquire diverse amounts of scientific data from the Shroud on-site. This team worked in an interdisciplinary manner so that conclusions reached could have multiple corroboration. The results of STURP were published in numerous peer-reviewed scientific journals in the early 1980's (Refs 1-11). A popular review of the work of the STURP team can be found in the National Geographic Magazine (Ref 12).

The major conclusions of the team were that the bloodstains on the Shroud are blood and that the body image is chemically a form of degraded cellulose. In other words, the body image is the result of a molecular change in the linen cellulose, with a chemistry similar to that induced by scorching (although a thermal explanation for the image seems unlikely). No extraneous chemical agents of any significance were detected that could be associated with the image. The body image was shown to reside on the surface (or uppermost) fibrils of the cloth. At the microscopic level, brownish colored fibrils in the body image could be seen lying atop and next to white fibrils that comprise the threads that make up the weave of the Shroud.

There are considerable microscopic surface debris on the Shroud that were picked up on sticky tape samples. For example, certain red particles were noted on some fibrils, but it was concluded that these are due to major microscopic erosions of the reddish blood regions. These red particles were presumed to have been distributed over the body image by simple contact transfer during folding and rolling for storage and display purposes of the Shroud.

The possibility that the Shroud of Turin is the burial cloth of Jesus comes primarily from a consideration of the many wounds found on the Shroud. In particular, the evident wounds of crucifixion in the wrists and the feet, numerous scourge-like marks over the back, puncture wounds on the top of the head, and a wound in the side all correlate well with the New Testament accounts of the Passion of Jesus.

Moreover, the Shroud and its image have numerous characteristics that are entirely consistent with a Jewish burial of the First Century (Refs 13-15). For example, the Man of the Shroud appears to be of Jewish racial type and was buried according Jewish burial custom. In particular, the blood on the Man of the Shroud was not removed before burial, which is mandated by Jewish law for a Jew who dies a violent death. In addition, the fingers of the Man of the Shroud are extended, which the Jews of the First Century ensured in defiance of contemporary pagan burial practices (e.g. as seen in Egyptian mummy configurations and statuettes). The dimensions of the Shroud can be expressed in the unit of the cubit used at the time of Christ. These and other indications of a Jewish character for the Shroud are consistent with the Jewish culture in which Jesus lived and died, and thus support the Shroud's authenticity.

However, in 1988 the Shroud was subjected to radiocarbon analysis. In spite of the above characteristics that point to the Shroud being the actual historic burial cloth of Jesus, the reported radiocarbon age turned out to be only 14th century (Ref 16). If valid, then the Shroud could not be the historic burial cloth of Jesus, but merely a product of the Middle Ages.

Nevertheless, the totality of the various types of historical and archaeological data concerning the Shroud are sufficiently compelling towards authenticity that we think it is unwise to tacitly accept the radiocarbon date without a rigorous critique of its applicability to the Shroud. For example, the late Dr. Max Frei reported finding numerous pollens on the Shroud from plants that grow only in the Middle East (and not in Europe). If the Shroud dates only from the fourteenth century, and we know historically that it has been in Europe continuously from that time, then we must critically ask: How did all the pollens from the Middle East come to exist on the Shroud?

We can also readily observe in Eastern Christianity a profusion of Shroud-like icons (e.g. Christ's face on cloth, images of Christ rising out of a box with arms folded in front, etc.) These traditions well predate the radiocarbon's fourteenth century conclusion. Moreover, these traditions are so entrenched into Eastern Christianity that they presuppose a prototype upon which they are based. Because the Shroud shows no evidence of being the handiwork of human craftsmanship, and exhibits many of the intrinsic characteristics of these icons, it is entirely reasonable to hypothesize that the Shroud is, in fact, THAT prototype and, therefore, must predate the fourteenth century proposed by the radiocarbon measurement. Certainly, more scholarly research is needed to clarify such intriguing possibilities.

If the radiocarbon date is in error, it is necessary to show why. There are a variety of suggestions that have been proposed, all of which would make the radiocarbon date appear too young. However, we presently think that the most fruitful avenue of research is that inspired by some scientists in Russia who have reported seeing major shifts in the radiocarbon date of linen samples that have been incubated at modest temperatures (Refs 17,18).

This research is interesting because we know that the Shroud endured a significant thermal event during a fire in 1532 while in Chambrey, France. The entire cloth has yellowed and in some places scorched and burnt. Thus, based on the Russian studies, it is logical to suspect that the 1532 fire altered, perhaps significantly, the radiocarbon date of the Shroud. This effect appears to be related to an interaction with carbon dioxide in the surrounding air that favors significant chemical enrichment of the sample by those carbon dioxide molecules that contain the heavier carbon isotope (i.e. C-14).

It is necessary that the Russian experiments be confirmed independently. However, the University of Arizona, one of the original radiocarbon daters of the Shroud, has published that they were unable to confirm the Russian experiment (Refs 19,20). We, however, have performed studies indicating that the conditions of the Arizona experiment may have caused any enrichment in carbon-14 to dissipate before the end of their experiment (Ref 21). Such late time dissipation can, in fact, be seen in the Russian data, but at a much slower rate.

We believe it is important to understand exactly what the Shroud is because, if authentic, it would arguably have been the closest physical object to the very cornerstone event of Christian faith, the burial and Resurrection of Christ. The New Testament does not indicate that anyone directly witnessed what happened in the sealed, dark tomb of Jesus; but if the Shroud of Turin were to be shown to be the actual burial cloth of Jesus, then it might provide an unprecented witness to the event of that first Easter morning (Ref 22).

Such an achievement, if indeed it is even possible, will come only with considerably more research (e.g. Refs (23-24)), which certainly must include a new direct examination of the Shroud. Because of the potential importance of what the Shroud could mean for mankind, we must insist on only the highest standards of science and scholarship. We must be open to whatever outcome future research will give us, whether it will be proved to be merely an inauthentic Shroud or a Shroud that was, in its own way, a direct witness to the Resurrection.

References

1. J.P. Jackson et al.,"Correlation of image intensity on the Turin Shroud with the 3-D structure of a human body shape", Applied Optics, 15 July 1984, pp. 2244-2270.

2. L.A. Schwalbe and R.N. Rogers,"Physics and Chemistry of the Shroud of Turin - A Summary of the 1978 Investigation," Analytica Chimica Acta, 135, (1982), pp. 3-49.

3. J.H. Heller and A.D. Adler,"A Chemical Investigation of the Shroud of Turin,", Can. Soc. Forensic Sci J, vol 14, (1981), pp. 81-103.

4. E.J. Jumper et al.,"A Comprehensive Examination of the Various Stains and Images on the Shroud of Turin", in Archeological Chemistry (American Chemical Society), Washington D.C., Chapt 22 (1983).

5. R. Gilbert Jr. and M.M. Gilbert, "Ultraviolet Visible Reflectance and Fluorescence Spectra of the Shroud of Turin," Applied Optics, volume 19, pp. 1930-1936, 15 June 1980.

6. S.F. Pellicori, "Spectral Properties of the Shroud of Turin", Applied Optics, volume 19, pp. 1913-1920.

7. S.F. Pellicori, "The Shroud of Turin Through the Microscope", Archaeology, volume 34, pp. 34-43, Jan-Feb 1981.

8. V.D. Miller and S.F. Pellicori, "Ultraviolet fluorescence photography of the Shroud of Turin", Applied Optics, volume 49, July 1981.

9. R.A. Morris et al.,"X-Ray Fluorescence Investigation of the Shroud of Turin", X-Ray Spectrometry, volume 9, 1980.

10. J.S. Accetta and J.S. Baumgart, "Infrared reflectance spectroscopy and thermographic investigations of the Shroud of Turin", Applied Optics, volume 19, pp. 1921-1929, 15 June 1980.

11. E.J. Jumper and R.W. Mottern,"Scientific investigation of the Shroud of Turin", Applied Optics, volume 19, pp. 1909-1912, 15 June 1980.

12. K.F. Weaver, National Geographic, 157, pp. 730-753, June 1980.

13. R.S. Jackson, "Hasadeen Hakadosh: The Holy Shroud in Hebrew", Actes Du Symposium Scientifique International, pp. 27-33, Rome, 1993.

14. R.S. Jackson, "Jewish Burial Procedures at the Time of Christ - A Jewish Cultural Approach", Actas del I Congreso Internacional sobre El Sudario de Ovidedo, pp. 309 -322, October 1994

15. R.S. Jackson, "The Shroud of Turin in Light of First Century Jewish Culture", Actes du III Symposium Scientifique International du CIELT, Nice, 1997.

16.P.E. Damon et al.,"Radiocarbon dating of the Shroud of Turin", Nature, vol 337, pp. 611-614, 16 Feb 1989.

17. D.A. Kouznetsov et al.,"Effects of fires and biofractionation of carbon isotopes on results of radiocarbon dating of old textiles: the Shroud of Turin", Journal of Archaeological Science, volume 23, pp. 109-121, 1996.

18. D.A. Kouznetsov et al.,"A Re-evaluation of the Radiocarbon Date of the Shroud of Turin Based on Biofraction of Carbon Isotopes and a Fire-Simulating Model", Archaeological Chemistry Organic, Inorganic and Biochemical Analysis, Mary Virginia Orna, Editor, American Chemical Society, 1996.

19. A.J.T. Jull et al., "Factors Affecting the Apparent Radiocarbon Age of Textiles: A Comment on 'Effects of Fires and Biofractionation of Carbon Isotopes on Results of Radiocarbon Dating of Old Textiles: The Shroud of Turin' ", by D. A. Kouznetsov et al., Journal of Archaeological Science (1996), 23, 157-160.

20. A.J.T. Jull et al., "Factors That Affect the Apparent Radiocarbon Age of Textiles, Archaeological Chemistry Organic, Inorganic, and Biochemical Analysis", Mary Virginia Orna, Editor, American Chemical Society, 1996.

21. J.P. Jackson and K.E. Propp,"On the evidence that the radiocarbon date of the Turin Shroud was significantly affected by the 1532 fire", Actes du III Symposium Scientifique International du CIELT, Nice, 1997.

22. J.P. Jackson, "Does the Shroud of Turin Show us the Resurrection?", Centro Espanol de Sindonologia, ISBN:84-605-7120-3, 1997.

23. K.E. Propp and J.P. Jackson, "Color and Intensity Analyses of the Shroud of Turin", Proceedings of the Third International C.I.E.L.T. Shroud Symposium, Actes du III Symposium Scientifique International du CIELT, Nice, 1997.

24. Jackson, R.S., "Jewish Burial Procedures at the Time of Christ - A Jewish Cultural Approach", Centro Espanol de Sindonologia, Valencia, ISBN: 84-930386-0-1, 1998.