The scientific research on the Shroud
As mentioned earlier, it is the first photograph taken in 1898 that initiates a totally new and fascinating period: that of the “scientific history” of the Holy Shroud.
The hypotheses on the origin of the impression
The question pertaining to the modality of the formation of the image was one of the first research themes which gave origin to a deep study by different scholars, right at the start of the 20th century. They wished to understand by which natural process a corpse would leave traces on a linen cloth characteristic of those visible on the Shroud.
Numerous theories were proposed in this period spanning over a hundred years. Many of them were also experimental attempts to reproduce (starting from a corpse or through an artificial method) a similar image to that of the Shroud. Someone thought that the imprint was caused by chemical reactions between the ammoniac evaporations emitted by the corpse and the aloe and myrrh (natural fragrant substances used in ancient times to honor the corpses) present in the linen; some others have thought that it could be radiation from the body or from some external source to the body. Some others have tried experiments using thermal energy generated from a statue of heated metal; others have also tried using red ochre to paint an image on a sheet of cloth, etc. In none of these cases were the experimental results really satisfactory (that is, being able to realize a similar image as that of the Shroud) and some of the characteristics of the image of the Shroud seem impossible to be produced to this day. The results obtained however, affirm with certitude that the image was produced through a natural process from the corpse of a human being, and exclude that it be due to the work of some artist through the use of a reproduction technique. In fact, the American scientists of the research group named STURP (Shroud of Turin Re-search Project) who in 1979 made direct experiments on the Shroud, confirmed through a complex series of tests, the absence of pigments and colors on the Shroud, proving, moreover, that the bodily image is absent below the blood stains (and therefore formed on it later) , which is merely some hundredths of a millimeter thick on the cloth’s surface and is “the result of cellulose decomposition, the oxidation-dehydration of the cloth’s surface” which took place through some unknown process and certainly not due to the use of artificial means.
Researches on the blood stains
The red stains visible on the Shroud were always considered to be blood stains. But absolute certainty required a detailed examination of the material found on these stains. In 1978 some samples of this material were taken by two groups of scholars (Italian and American) and the tests performed by them in the following years have confirmed it to be human blood of type AB.
The biological traces
In 1973 and 1978, through the application of some adhesive tapes on the Shroud, samples of micro traces containing pollen grains belonging to 58 floral plants were found. Since some of these come from plants that grow only in Palestine and in Anatolia (present Turkey) one can conclude that, besides Europe, it is highly probable that the Shroud had a prolonged permanence in those regions as well. Further research, conducted by scholars from Israel, has discovered other types of plants, reaffirming the above mentioned hypothesis.
A computer elaboration of the image
In 1977 some American scientists making an electronic elaboration of the image of the Shroud (by means of a special scanning process) discovered that it possesses three dimensional characteristics displayed neither by paintings nor by normal photographs. A year later an independent group of scholars from Turin also obtained three dimensional images of a high definition, so as to place in evidence numerous particulars otherwise not visible. For example, the traces on the right eyelid left by an object most probably identifiable with a Roman coin minted in the first half of the 1st century. They further succeeded in obtaining another advanced image of a face without the wounds and the bloodstains, obtaining in such away the real face of the man of the Shroud. Some years later they made an electronic elaboration parallel to the face of the man of the Shroud and of the main icons of the face of Jesus that date back to the first millennium of the Christian era, showing a high number of similar characteristics that make us consider the most probable hypothesis that the face of the man of the Shroud be the prototype of the Christian iconography (at least from the start of the 6th century).
The radiocarbon dating of the linen cloth
In 1988 three cloth samples were taken from the Shroud in order to determine its date with the radiocarbon method (the C14 dating test). The results obtained from three laboratories which conducted the tests dated the Shroud-cloth between 1260 and 1390 A.D.
These results are still a topic of wide debate between scholars concerning the reliability of the radiocarbon method to date an object with such historical and chemico-physical characteristics as those of the Shroud. The medieval dating contradicts various results obtained in other fields of research. Besides it is not easy to ascertain if in the course of time there no C14 was added to that present at the moment the linen was cut that was used to weave the Shroud. Studies done on ancient textiles have further opened up scientific debates on the date of the Shroud, rendering experimental results that seem to prove that both biological and chemical contaminations of the textile are prone to considerably alter the radiocarbon age of a cloth. Since the Shroud has certainly undergone contaminations which are biological (so prove the micro traces found on it) or chemical (as a consequence of the burning endured at Chambéry) the above experimental results deserve to be attentively studied and verified through the realization of a broader research program, and of new tests that evaluate the introduction of a factor of correction to the radiocarbon date of the Shroud textile. Hence, till now the problem of the date of the Shroud textile is not yet resolved.
The new method of conservation
In 1992 an international commission of scientists was assigned the charge of finding a new and more modern method of conservation of the Shroud. After some years of study and verifications, two new protection caskets were designed: one ensuring maximum security and used for the public exposition in 1998, 2000 and 2010 and another lighter one for ordinary conservation. In this the Shroud is placed horizontally, completely spread open, immersed in argon, an inert gas, protected from light and maintained in constant climatic conditions (temperature, humidity, pressure), and held under a monitored computer system. The conservation in an inert gas, argon (which does not react with most common chemical elements), is indispensable to arrest the growth of bacteria and to stop the progressive fading of the cloth (provoked by the natural process of oxidation due to the oxygen of the atmosphere) which is responsible for the progressive reduction of the visibility of the image. The two new protection boxes have the form of a parallel floor, whose lateral and inferior surfaces are made of a metallic composition and its superior surface is made of a bullet proof glass.
In 2002 the Shroud underwent an important and indispensable restoration. The patches stitched in 1532 on the holes provoked by the fire, were removed and were substituted with the so-called Dutch cloth. The restoration has permitted the removal of polluting materials present under the patches, residues of the fires of Chambery in 1532 – materials which are accurately gathered in special sealed and catalogued containers.
The work of improving the conditions of conservation of the Shroud which took effect in the decade 1992-2002 constitutes a milestone in the history of the Shroud, inasmuch as it guarantees optimal modern conditions of conservation which will allow future generations to continue to admire this unique and fascinating image.