Shroud of Turin - A Photograph by Leonardo da Vinci

It helps (well it helped me!) to remember that there are three main aspects to the mystery surrounding the Shroud of Turin:

1. The age of the Shroud (separable into two parts - date of cloth and date of image).

2. The provenance of the Shroud (ie can its movements be re-traced back in time and travel to the place where it was created).

3. The mechanism by which the image was formed (also separable into two parts - the blood image and the body image).

This post considers only aspect 3, the image formation mechanism.

It was suggested in the early 1990s (by Lynn Picknett and Clive Prince in Turin Shroud: How Leonardo Da Vinci Fooled History ,1994 edition revised and updated in 2006, and separately at about (1993) the same time by Prof Nicholas Allen) that the body image was a form of early photograph made using a camera obscura, itself a technology known in the Middle Ages.

Picknett and Prince suggested that it was done by Leonardo da Vinci in 1492, Allen argued that it pre-dated Leonardo (born 1452) and was by an unknown medieval photographer some time before 1357 (when the Shroud was first being shown in France). At any rate, both proposed that the body image is a photograph.

As a reminder, the carbon dating conducted in 1988 dated the flax in the cloth (not the image) as having been harvested between 1260 and 1390. The only point of relevance for present purposes being that the 1988 carbon dating does not rule out either Picknett/Prince or Allen.

I read the 2006 edition of the Picknett/Prince book a few years ago, and the photograph idea has been popularised in a number of recent TV documentaries. I have commented elsewhere that "if an object looks like a photo, and has the properties of a photo ... then the hypothesis that it IS a photo seems reasonable".

But does the image on the Shroud look like a photo, or have the properties of a photo?

There are significant objections to the idea that the image is a photo. Until relatively recently, these objections were 1-5 below:

1. The body image contains realistic 3-dimensional information relating image density at any particular point to the distance between the cloth and the body at that point. This is a property that is not possessed by a photograph, where density of the image is determined by the amount of light received at any particular point.

This property was first identified in 1902, and was first demonstrated visually in 1976. It enables the generation of a 3-D image of the figure on the Shroud.

2. There are a number of blank areas on the body image, most notably above and below both forearms. If the image had been created by means of frontal illumination (as would be the case if it were a photograph from a camera obscura), this distinctive absence of image could not exist, since front lighting would not cast any shadows at all, let alone both above AND below the hands/forearms.

3. There is lateral distortion on the image. Just above the knees, the base of the right thigh bulges out markedly, and the image of the right shin extends out from the knee further than the left. Both thighs widen out on either side towards the top. Such distortion would not appear in a photograph.

4. Those who maintain that the body image is a photograph argue (if they say anything on the subject at all) that the blood image was added ("painted") after the body image had been "photographed". But research done by STURP (Shroud of Turin Research Project) and others has shown that there is no body image underneath the bloodstains, indicating that the bloodstains were on the cloth before the body image was formed.

5. There is no chemical or spectroscopic evidence for the presence, on the Shroud, of the image retaining photographic media proposed by Picknett/Prince (egg white and chromium salts) or Allen (silver salts), or of the expected product of their chemical reaction to create the Shroud body image photographically.

In addition to these objections to the photograph theory, now there is also "double superficiality":

6. In 1532, the Shroud was stitched onto a backing cloth which prevented observation of the rear surface (r/s) of the Shroud. In 2000 the central part of the backing cloth was unstitched to allow passage of a scanner which acquired images of the r/s corresponding to the two images on the front surface (f/s). In 2002, the Shroud was the subject of "conservation" work, during which the backing cloth was completely unstitched and the r/s photographed in full.

The 2000 scan and 2002 photos both revealed the presence of an image on the r/s of the Shroud. This r/s image presents as a photographic negative, is superficial (because only the topmost fibres bear the image), and includes 3-D information (in other words, its properties are exactly like the front image). The r/s image corresponds to the face, and probably also the hands, of the f/s figure. The r/s image of the face corresponds in form, size and position with the image on the f/s. The internal part of the linen fabric does not bear an image. The face image is therefore said to be doubly superficial.

The problem that the double superficiality poses for the photograph theory is that there is no way that light could, as part of a photographic means of formation of the body image, have penetrated the Shroud cloth and reacted with photographic medium on the r/s.

Neither Picknett/Prince, nor Allen, nor anyone else I have come across, has satisfactorily dealt with any one of these six problems, and in most cases their writings in support of their hypotheses simply ignore these problems.

On this basis, the body image on the Shroud does not look like a photograph, and it does not have the properties of a photograph.

It would follow that the Shroud of Turin is not a photograph, whether by Leonardo or anyone else.

Pendragon- I suspect some the issues could be dealt with by the length of exposure required by Da Vinci using sunlight.

If it is genuine then the church should allow proper scientific analysis. They will not for the obvious reason.

The idea that because there are some issues with exactly how it was done does not make it magic, or in any way genuine.

This is the much flawed "I do not know, therefore god did it" argument that is very silly. If the catholics would like to offer unfetered access and testing I am sure it could be sorted out. Or do you also think that the Easter Island stones, Stonehenge, the crystal skulls etc are all evidence of a deity/aliens/whatever lunacy you wish to promote?

I have heard, but not verified, that the energy required to produce the negative image on the shroud is roughly equal to an atomic explosion. In Hiroshima, images are imprinted on the few remaining walls..And, on an unrelated point, why would a forger produce a negative image in an age where bones, hair and real tangible tems wre worshipped? Why produce a negative in an age when the positive image would have been of more benefit? Only modern technology reveals the true image. Did iconoclastic christians forsee modern technology?

I wish they would make a carbon dating of the "bones" in the three-kings-shrine in the cathedral of cologne.

Tell us more, RK, svp.

CAS -
- " I suspect some the issues could be dealt with by the length of exposure required by Da Vinci using sunlight."
As someone with a diploma in photography and a fair amount of practical experience, I cannot see how length of daylight exposure would in any way affect any of the issues addressed.

- "If it is genuine then the church should allow proper scientific analysis. They will not for the obvious reason."
What on earth do you men by "genuine" here? This is jumping the gun. The Church makes no claims. The reason the Church denies access is because they do not want the precious artefact irretrievably damaged, lost or destroyed. It is actually in the Church's best interests to know as much about it as possible.

- "The idea that because there are some issues with exactly how it was done does not make it magic, or in any way genuine."
Correct, but it remains unexplained and therefore a mystery.

- "This is the much flawed "I do not know, therefore god did it" argument that is very silly"
You and your ingenuous atheist friends may argue this, but you are totally misrepresenting most of the Christians I know, including Roman Catholics, who would leave it as simply "unknown".

- "Or do you also think that the Easter Island stones, Stonehenge, the crystal skulls etc are all evidence of a deity/aliens/whatever lunacy you wish to promote? "
All these things, which do not yet have any viable scientific explanation (and I would include some instances of crop (etc.) circles, and ball lightning) are simply mysteries and unexplained. Since God cannot be explained or even defined by science, except by summary dismissal as a figment of the imagination, they share this quality of inexplicable, going beyond the limits of contemporary scientific knowledge and method, and in this way may be associated.
If for example, it could be shown that brain-waves (or thoughts) can physically exist and operate outside of and independently of the brain, this would give support to a lot of "paranormal" phenomena, and go some way to proving there can be intelligence without matter, which clearly has relevance to the concept of God. But, for the time being, this is just science-fiction, discounting the Russian military investigation of telepathic communication with submarines.

Pendragon - "three main aspects to the mystery surrounding the Shroud of Turin"

Congratulations! Great (and concise!) summary of the arguments and facts to date. I look forward to parts 1 and 2.
But you have not addressed the ochre rubbing technique.

Michael- the exposure time was a day at least- in a day the sun appears to travel from one horizon to the other casting it's light differently.

The catholic church have no interest in the truth. Catholics hail it as the shroud of christ and it attracts pilgrims and money as do all the shabby collections of bones, wood and other nonsense the church has used for centuries to get money from the gullible.

If it is simply "unknown" why not let the scientists attempt to make it unknown? Because it is not genuine, they know it, and so does everyone else who thinks about it.

It is intriguing from a mystery point of view, very interesting, but as a religious relic- a con.

http://en.wikipedia.org/wiki/Shrine_of_the_Three_Kings

When it was last opened in 1864, they found a lot of bones.
The part of the three kings contained a skull from a man, aged 25 to 30 years, a male skull aged 10 to 12 years, and again a male skull, aged 50 years.

Isn't it Cologne Cathedral where there is a lead lined crypt, or lead lined sarcophaguses with the mummified bodies of mediaeval builders? Though I wonder why they would have put building workers' or stone masons' bodies actually in the crypt of the cathedral?

I really don't know.
Alot of people are buried there.
Maybe this will help:
http://www.koelner-dom.de/index.php?id=72&L=1

CAS -
- "the exposure time was a day at least- in a day the sun appears to travel from one horizon to the other casting it's light differently."
So? Just how would this affect the issues raised, except by making the image very fuzzy and out of focus with indefinite shadows, and making the prior positioning of the blood-stains even more impossible?

The Catholic Church currently makes no claim as to the Shroud's authenticity as the original winding sheet of Jesus, only of this possibility, and that it's date and origins are unproven and that there are periodical "historical" mentions of "it" from the first century. What a number of Catholic believers and pilgrims choose to believe is another story.

If the scientists could satisfactorily date it and point to its provenance and method of fabrication, there would then be little or no mystery.

Again I ask you "genuine" what? This depends entirely on the claims made and by whom. It is certainly, for the time being, a genuine mystery. As I have stated before, the real question is what it IS, and not what it IS NOT! I am quite convinced that it is not a "genuine Da Vinci" but I do not know just what it is.

As a religious relic, the only genuine claim that can be made about it is that it represents quite faithfully the type of crucifixion described in the NT, EXCEPT for the nails in the wrists, quite contrary to both the description and the tradition.

If the catholic church make no claims about it why do they revere it?

It is a mystery but nothing else. It should handed to a museum for proper investigation. No surprise that it has not been, the church is not renowned for seeking the truth.

CAS - "If the catholic church make no claims about it why do they revere it? "

They who?

The Catholic Church IS a museum; one of the richest in the world! And it hangs onto its precious possessions. Its understanding and definition of truth is somewhat different from yours.

Why do the church hang onto archeological and cultural treasures? This question from a nation holding on to the Elgin Marbles and variouis other Egyptian , Chinese and South American artifacts. Hmmm...

Spin good point. Oh now I think about , not a good point.

As far as I am aware the Elgin marbles are not reputed to have been made by a deity, museums hold artefacts of interest to all, religions hold relics to bolster their spurious claims. Which is why I stated that the shroud should be given to a museum.

"This question from a nation"

No, this question from a person.

[Customers don't think this post adds to the discussion. Show post anyway. Show all unhelpful posts.]

Spin- what are you on about now?

Sam: True: Sorry. I just logged onto this thread from the Politics forum in which I find one particular thread most amusing, entitled "Reasons to be ashamed to British"...=) I forgot to switch off my generalisation of the british public and the british individual and switch on the belief that brits are actually morally good people. =)

CA; No offence, but I think I am quite clear. To put it simply, when you complain about other cultures, politics or religion remember the words "Pot", "Kettle" and "Black"...

Spin- you may *think* you are clear. Reread your post to which I replied. Then reread my reply. Think about it for a while and see where you went wrong.

[Customers don't think this post adds to the discussion. Show post anyway. Show all unhelpful posts.]

Spin- the fact you cannot seem to keep up and remember your own posts his hardly my fault.

CA: Sorry: you lost me. No offence, but unlike your arguments, my arguments do not contradict themselves. Instead of slagging me off, reply to my point that your condemnation of the Vatican "holding on" to archeological treasures differs from the british and americans holding on to artifacts that rightfully belong to the nation in which you imperialists dug them up...I cannot put my point much simpler than that..(Sorry, my genius forbids it =)