Miracle of the Shroud II: The Second Coming

[wardenclyffe]

This is a known issue. The very same issue that raised it's head with regard to whether syphilis came from the new world to the old, or vice versa. It is known that a seafood diet will skew carbon dating. Feel free to tell us all what exactly was the diet of the tablecloth. I cannot see what diet a cloth might have had. As far as I know, the tablecloth of turin had no diet whatsoever.

I'm pretty sure Hugh's point was that shells had nothing to do with the (presumed) gesso on the shroud, but that the calcium carbonate came from ancient chalk or limestone.

Ward

 

[hugh farey]

This is a known issue. The very same issue that raised it's head with regard to whether syphilis came from the new world to the old, or vice versa. It is known that a seafood diet will skew carbon dating. Feel free to tell us all what exactly was the diet of the tablecloth. I cannot see what diet a cloth might have had. As far as I know, the tablecloth of turin had no diet whatsoever.

It is known to you. It was not apparently, known to Peregrinus, and now he is better informed. However, I do not believe that if the Shroud was prepared with gesso, the calcium carbonate used derived from shells or seafood, but much more likely from chalk. Actually I think it unlikely that any carbonate would survive four hours of hydrochloric acid at 80°C, but if it did, it would have the effect of making the Shroud appear older, which could then explain why the Oxford date was significantly different from the other two.

 

[abaddon]

It is known to you. It was not apparently, known to Peregrinus, and now he is better informed. However, I do not believe that if the Shroud was prepared with gesso, the calcium carbonate used derived from shells or seafood, but much more likely from chalk. Actually I think it unlikely that any carbonate would survive four hours of hydrochloric acid at 80°C, but if it did, it would have the effect of making the Shroud appear older, which could then explain why the Oxford date was significantly different from the other two.

And this is why I do not trust you. You spend inordinate time dissembling as a skeptic, yet often throw the gambit of "but what if".

I'm sorry if it offends you, but as far as I can see, you are attempting to trojan horse your way into the discussion, and you can imagine my opinion of such behaviour.

 

[wardenclyffe]

And this is why I do not trust you. You spend inordinate time dissembling as a skeptic, yet often throw the gambit of "but what if".

I'm sorry if it offends you, but as far as I can see, you are attempting to trojan horse your way into the discussion, and you can imagine my opinion of such behaviour.

I don't see that, but to each his own. I think Hugh is a believer in the story of Jesus, but he is not a believer that the shroud ever touched his body. At least that's what I get when I read his stuff. He seems to accept scientific and historical reality. If he also maintains faith in the supernatural, that's fine. Belief in a god does not make everything a person ever says suspect. I'll accept that I might be interpreting this all wrong, but I do not see him bringing unnecessary drama to this thread.

Ward

 

[wardenclyffe]

It's also OK to not trust someone without attacking everything they say, especially when you agree with what they say.

Ward

 

[hugh farey]

I've no idea what you're on about, abaddon, but I take no offence. I was criticising the paper presented by Ray Schneider at the recent St Louis conference, which Jabba thought might have cast reasonable doubt on the radiocarbon dating. I believe I did so quite comprehensively. I believe I pointed out something that has not been previously recognised, which is that any contamination present on the Shroud as described by Schneider would have the opposite effect from what he hoped, making the Shroud appear older rather than younger.

I'm sorry if this offends you, but your opinion of my behaviour is of no importance to me whatever.

 

[Slowvehicle]

This is a known issue. The very same issue that raised it's head with regard to whether syphilis came from the new world to the old, or vice versa. It is known that a seafood diet will skew carbon dating. Feel free to tell us all what exactly was the diet of the tablecloth. I cannot see what diet a cloth might have had. As far as I know, the tablecloth of turin had no diet whatsoever.

A few observations:

1. High-quality gesso was more often made with marble dust, ground very fine, than with chalk. The end result is whiter, and more durable, with a far better "tooth", than chalk or gypsum gesso (partner went through a period of making historic ikon-analogues with traditional media, including rabbit-skin sizing and egg-yolk tempera--as "domestic goddess and artwright", I got to learn how to do all the period-appropriate mixing, grinding, and conching).

2. Whether chalk, gypsum, or marble, gesso contamination would (if, as has been pointed out) not removed by the cleaning protocol) skew the results of ¹⁴C dating in the direction of making the tested sample seem older than it actually is. In other words, if anything, claiming gesso contamination means that the CIQ is newer than the mid-12^th Century CE. The CIQ was "discovered", displayed, and then denounced as a fraud by 1389-1390 CE, so it is, in fact, manifestly not more recent than that.

3. What authentisti do not seem to realize is the greater significance of gesso. If the CaCO₃ found in significant amounts on the CIQ is, in fact, gesso, it clearly indicates that the "image" is a painting. The purpose of gesso (and, to a lesser extent, size) is to cover a textured, porous surface (such as woven linen) with a thin, smooth, non-porous layer through which liquid pigments would not bleed, and in which liquid pigments would not "feather".

This is the issue I raised, more than a year ago, about sizing. The presence of gesso in the CIQ strongly indicates that the linen was painted , and not earlier than the 11^th Century CE or so.

Further, even if CaCO³-based sizing had been in common use in the 1^st Century CE, the very qualities that make gesso so useful for making cloth a suitable surface for painting mean that sized cloth would be singularly unsuitable for wrapping a freshly-washed body.

 

[Dinwar]

It is known to you. It was not apparently, known to Peregrinus, and now he is better informed.

Ignoring the marine bias is akin to claiming to be a five-star chef and not knowing how to clean a cast-iron skillet. The marine bias is one of the most common in C14 dating, seeing as how most of the fossil record is shallow marine invertebrates which have a strong tendency to use CaCO3 in their shells. I'd have to re-read my isotopic geochem book to see when the marine bias became known, but it's been known for a long time (for radiocarbon dating knowledge).

I'd need to see some strong evidence that superficial contamination like this wouldn't be removed from the material prior to processing, though.

 

[pgwenthold]

Ignoring the marine bias is akin to claiming to be a five-star chef and not knowing how to clean a cast-iron skillet. The marine bias is one of the most common in C14 dating, seeing as how most of the fossil record is shallow marine invertebrates which have a strong tendency to use CaCO3 in their shells. I'd have to re-read my isotopic geochem book to see when the marine bias became known, but it's been known for a long time (for radiocarbon dating knowledge).

I'd need to see some strong evidence that superficial contamination like this wouldn't be removed from the material prior to processing, though.

Note that all the samples were cleaned in dilute acid. Guess what carbonates do in acid?

I always figured something like this was why they used acid in the first place! Although nitric acid is also an oxidant and that's a good approach for getting rid of dirt, too.

 

[Dinwar]

Note that all the samples were cleaned in dilute acid. Guess what carbonates do in acid?

My wife did some rock-cores in Florida once. Had to do VOC (volatile organic compound) testing on groundwater from the holes. To preserve the samples, VOC vials come pre-preserved with some acid in them--I think like 0.5 ml of HCl, something like that (depends on the lab, and whether you're dealing with rock, water, soil, or sediment). You're not supposed to have any air bubbles in them, because it'll provide headspace for volatilizaiton. She argued with the lab for two weeks about her techniques, and why the vials were coming in either with huge bubbles or flushed of preservative. Finally she convinced the lab that taking groundwater samples IN A REEF would result in an abnormally high CaCO3 concentration. They sent unpreserved vials (7day hold time in EPA Region 9, instead of a 14 day hold time), and everything worked perfectly.

I always figured something like this was why they used acid in the first place!

Most likely not. Acid washing is more or less standard; it's a fantastic way to break particles off of the material being tested. I used to wash glassware in nitric acid, despite not using any basic components in the experiments.

 

[Charles Freeman]

The techniques of making gesso are well known. It was a mixture of animal proteins, usually rabbit skin glue, and calcium carbonate - though calcium sulphate was more common south of the Alps. The same process is used to this day to seal linen before it is painted on. It was therefore very significant that STURP found what they termed 'large' quantities of calcium carbonate on different parts of the Shroud. There is also good evidence for animal proteins.

STURP were woefully inadequate as a team researching an ancient textile as they knew nothing of this. They were also surprised that the images ( as they remained probably after the disintegration of the pigments) were only in the outer fibrils of the linen but this is exactly what the medieval manuals suggested. So despite STURP making a big thing about this not being a painting, they provide good evidence that it once was.

In their report of 1981 STURP also noted the the surface of the Shroud had a 'frosty' appearance although after their examination in Turin they were only working from their sticky tapes, an important source of evidence but one that seems to have disappeared. Another worrying aspect of the STURP adventure. These tapes represent the best external source of material on the Shroud so long as the Vatican halts further testing but how can independent scholars get access to them? Perhaps the 32 tapes, taken from different parts of the Shroud, have not even been preserved together, perhaps they have not even been conserved properly. I have never been able to find out.

I am not sure why Hugh rules out gesso when calcium carbonate was its most common component. Remember that the Shroud is a standard artefact for its times, nowhere near the top in quality. The.presence of gesso, hence the foundation of an original painting, would appear the best-fit hypothesis.

 

[hugh farey]

I am not sure why Hugh rules out gesso when calcium carbonate was its most common component.

No, Charles, on the contrary, I am ruling it back in! You know that one of my objections to the 'flaked painting' hypothesis is that there seems to have been a totally uniform dispersion of all the media involved. If there are, in fact, gradients of calcium carbonate across the Shroud, and particularly at its edges and fringes, then that is much better evidence for environmental deterioration. If gradients for red ochre could also be found, that would be better still. Everything that Slowvehicle said in his last post is quite correct.

 

[catsmate]

Note that all the samples were cleaned in dilute acid. Guess what carbonates do in acid?

I always figured something like this was why they used acid in the first place! Although nitric acid is also an oxidant and that's a good approach for getting rid of dirt, too.

<snip>Most likely not. Acid washing is more or less standard; it's a fantastic way to break particles off of the material being tested. I used to wash glassware in nitric acid, despite not using any basic components in the experiments.

Yep, the three labs used a variety of techniques. Including, in some cases, 80°C 5% hydrochloric acid baths for several hours. I don't see any chalk persisting after that treatment.
I'd be surprised if chalk survived the first stage of scraping, hot ether baths and ultrasonics.

 

[Akhenaten]

I've been up in the Wadi for a bit.

Any evidence for a 2,000-year-old tablecloth yet?

 

[catsmate]

I've been up in the Wadi for a bit.

Any evidence for a 2,000-year-old tablecloth yet?

None. At least for the SoT, there was an actual burial cloth but it's noting like the supposed shroud.

 

[Craig4]

As an archeology student, I'm just dying to know what the hell difference it makes that there was no archeologist present when the sample was taken when there were two textile experts there? What is it you imagine an archeologist could tell you that the experts in textile could not? The shroud is there completely out of context to when and where it was "found". There's no stratigraphy and no other artifacts found with it to look at. There's just not much for an archeologist to study here. There are specialists in textiles and artifact restoration who might add value but more than the textile experts?

 

[Slowvehicle]

As an archeology student, I'm just dying to know what the hell difference it makes that there was no archeologist present when the sample was taken when there were two textile experts there? What is it you imagine an archeologist could tell you that the experts in textile could not? The shroud is there completely out of context to when and where it was "found". There's no stratigraphy and no other artifacts found with it to look at. There's just not much for an archeologist to study here. There are specialists in textiles and artifact restoration who might add value but more than the textile experts?

The claim has been bruited about the the textile "experts" were "in on it"; either deceived, or montrously incompetent, or simply dishonest.

Whereas, of course, archaeologists are above reproach.

Or something like that.

 

[MRC_Hans]

As an archeology student, I'm just dying to know what the hell difference it makes that there was no archeologist present when the sample was taken when there were two textile experts there?

It is simply a straw to grasp for those who desperately want to discredit the C14 investigation which, beyond any sensible doubt, confirms the historical source about the age of the shroud.

Hans

 

[Craig4]

The claim has been bruited about the the textile "experts" were "in on it"; either deceived, or montrously incompetent, or simply dishonest.

Whereas, of course, archaeologists are above reproach.

Or something like that.

Clearly the advocates of that theory don't know that the rarest of all archeological finds is a steady job.

 

[sackett]

Am I OT? Very well then, I am OT!

...beyond any sensible doubt....

By god, I like that phrase! Beats "reasonable doubt," because reason can be perverted all to hell and brast if you start with a faulty premise.

Maybe I'm on topic after all. Jabba? Hello?