Freethought & Rationalism Archive

leonarde · 03-28-2005, 02:51 PM

Posted by Happy Wonderer:

Quote:

That was not a very convincing rebuttal. The actual article can be found here.

Points:

1) I was not trying to convince or 'rebut' anyone. I was trying to supply information for those who <comment deleted> are genuinely interested in this subject.

2) the URL that Happy Wonderer links includes this:

Quote:

Simple Chemistry Proves the Shadow Shroud Wrong

One need only turn to many articles published in peer-reviewed scientific journals to find out about the chemistry of the image. Wilson should have done some basic research before writing his shadow shroud theory. Christianity Today's editors should have sought out scientific opinion before publishing a pseudo-scientific article on the shadow shroud. The same can be said for ABC News. The papers in the peer-reviewed scientific journals don't explain for certain how the images were created and they don't opine on the Shroud's authenticity. They only present scientific fact. (See list at right).

The image on the Turin Shroud, the very thin layer of caramel-like substance, 180-600 nanometers thick, is thinner than most bacteria . The layer can be seen by phase-contrast microscopy. And with a scanning electron microscope the fine crystalline structure of the carbohydrate layer can be discerned. The image resists normal bleaching by chemicals or by sunlight. If the image were formed by a bleaching process, particularly an absence of bleaching as Wilson's proposes, it would bleach out.

Phase-contrast photomicrograph of a fiber and its image bearing coating. The coating is composed of starch fractions and saccharides.

The image on the Shroud of Turin can be scraped from the cloth, pulled away by adhesive and reduced with a diimide reagent, leaving colorless, undamaged linen. That cannot be the case with Wilson's image.

The picture on the right is a close up some Shroud of Turin fibers. The brown color is the caramel-like product, a melanoidin; the same stuff that gives beer its color, toasted bread its brown, and bodies their tan from sunless tanning lotions.

Wilson's proposed chemistry contradicts the scientific evidence. (See image-bearing coating picture in the right-hand column).

The Problem with Blood for the Shadow Shroud

There is the matter of the bloodstains. There is no image underneath the bloodstains. This means that wherever there was blood on the cloth it inhibited image formation. This cannot work in reverse. Wilson has failed to comprehend this problem.

The Problem of the Second Face and the Shadow Shroud

The simple fact that a second face has been discovered on the backside of the cloth is a major problem for Wilson's Shadow Shroud. He was unaware. But when he found out about it he responded: "So, for now, I am undaunted by Fanti's findings [=the second face], though I am aware that my confidence could yet vanish, as they say, like the morning dew."

It is not possible to superficially and selectively not bleach both sides of a cloth and bleach the inner fibers between both surfaces with sunshine. Period.

But that's just one aspect. The URL goes on about the absence of suitably high quality glass in the posited timeframe:

Quote:

Glass - Shadow of Doubt

The type of glass needed for Wilson's proposed shadow shroud process did not exist in 1357, the latest possible date for the Shroud of Turin if it was a fake-relic. No one questions that the Shroud existed by then.

Yet, it wasn't until the nineteenth century that glass suitable for Wilson's shadow shroud could be produced. The first flat plate glass wasn't produced until 1688. Before then, plate glass was blown plate, which was rare, very limited in size and very distorted. Glass, very rare in 1356, was poor quality with many imperfections. According to the PPG Industries website:

Flat glass for windows was still rare during much of the 17th and 18th centuries. Small panes were made by blowing a large glob of glass, removing it from the blowing iron and then rotating the glass quickly so it would spread and flatten. Such glass had a dimple in its center, many air bubbles and a pattern of concentric circles, but it was transparent and effective in keeping out the weather. At the end of the 17th century, the French learned how to grind and polish cast glass to produce plate glass, but only the rich could afford it.

Great strides were made in the manufacture of flat glass during the 19th century. Compressed air technology led to flatter, better glass panes. Controlled amounts of air were used to blow a large glass cylinder, which was slit lengthwise, reheated and allowed to flatten under its own weight. Large, relatively inexpensive lites of glass were produced in this manner.

(emphases added by leonarde)
Thank you, Happy Wonderer!

3) ANOTHER reason I felt no reason to "rebut" anything is that the previous posts by Clivedurdle buttress what I said about da Vinci's notebooks: only instead of the 50 or so pages I imagined in said notebook(s), apparently upwards of 5000 pages have come down to us. With nothing in them about ANY protophotographic technique. Thank you, Clivedurdle.

4) Finally I should mention something else: (proto)photography as the source of the Shroud image is NOT a new idea. It began with the first photos taken of the Shroud in 1898. That's when it was noticed that the image was itself very like a film negative. However, for a host of historical (ie chronological), and technical reasons, this was all but abandoned in the late 20th Century. Wilson's 'contribution' is to 'resurrect'-------excuse the expression------this tired old nag for another trot around the track. He, like his uncritical supporters, apparently is largely ignorant of the vast body of scientific knowledge on what the full range of characteristics of the image is. Once again: see:Schwortz's paper, "Is the Shroud of Turin a Medieval Photograph? A Critical Examination of the Theory"
http://www.shroud.com/pdfs/orvieto.pdf ). It was written in 2000. After a century or so of speculation about such a (proto)photographic technique. Written by STURP photographer Barrie Schwortz.

Cheers!

Vorkosigan · 03-28-2005, 03:02 PM

None of your other points are worth much, but this point about technology is devastating.

Quote:

Flat glass for windows was still rare during much of the 17th and 18th centuries.

Quote:

It was written in 2000. After a century or so of speculation about such a (proto)photographic technique. Written by STURP photographer Barrie Schwortz.

Articles by pro-Shroud types about an obvious medieval fake are usually worthwhile only for their entertainment value. Even if the technology remains a mystery, the object was already known in medieval times to be a fake.

Vorkosigan

leonarde · 03-28-2005, 03:13 PM

I really have NO idea where you are coming from Vorkosigan. Are you claiming that flat glass existed in the 15th century???

doubtingt · 03-28-2005, 03:49 PM

Quote:

Originally Posted by leonarde

3) ANOTHER reason I felt no reason to "rebut" anything is that the previous posts by Clivedurdle buttress what I said about da Vinci's notebooks: only instead of the 50 or so pages I imagined in said notebook(s), apparently upwards of 5000 pages have come down to us. With nothing in them about ANY protophotographic technique. Thank you, Clivedurdle.

Cheers!

Are you sure about that? The 2 hour National Geographic special showed a drawing of a camera obscura in Da Vinci's notebooks, notes about some experiments with with it, plus there were references by Da Vinci to the early Arab use of photosensitive chemicals.

leonarde · 03-28-2005, 03:58 PM

Quote:

Originally Posted by leonarde

3) ANOTHER reason I felt no reason to "rebut" anything is that the previous posts by Clivedurdle buttress what I said about da Vinci's notebooks: only instead of the 50 or so pages I imagined in said notebook(s), apparently upwards of 5000 pages have come down to us. With nothing in them about ANY protophotographic technique. Thank you, Clivedurdle.

Cheers!

Are you sure about that? The 2 hour National Geographic special showed a drawing of a camera obscura in Da Vinci's notebooks, [...]

Well then, I stand corrected. But my understanding is that Wilson's method is NOT the 'camera obscura' one........

leonarde · 03-28-2005, 04:17 PM

mention that the unbiblical nature of the Shroud that spin sees is a perception shared by someone (page 4 points 1 and 2) at this website:
http://www.letgodbetrue.com/bible/he...d-of-turin.pdf

Happy Wonderer · 03-28-2005, 07:05 PM

Quote:

Originally Posted by leonarde

1) I was not trying to convince or 'rebut' anyone. I was trying to supply information for those who <comment deleted> are genuinely interested in this subject.

I'm sorry if I wasn't clear, I was referring to the website as a rebuttal of Wilson's experiment. I'm not attacking you, in fact I am happy that you provided the website. The link I gave was from that website, you just had the front page and it took a bit of hunting to find what I wanted to discuss.

My interest is in how the shroud was made and exploring Wilson's hypothesis. The author of the website is engaging in apologetics, especially apparent as I pointed out when he has two different claims for what the image is composed of depending upon which argument he is making.

Quote:

2) the URL that Happy Wonderer links includes this:
But that's just one aspect. The URL goes on about the absence of suitably high quality glass in the posited timeframe

emphases added by leonarde)
Thank you, Happy Wonderer!

I addressed this. The absence of plate glass is a red herring, high quality stained glass windows have existed for a very long time. To show that the lack of plate glass was a problem for the hypothesis, one would have to show that the image could have only been made with some form of high quality glass. I do not see how one could make that claim, since the image is so faint and the media that it is on is so decayed. Heck, the thing went through a fire!

Quote:

ANOTHER reason I felt no reason to "rebut" anything is that the previous posts by Clivedurdle buttress what I said about da Vinci's notebooks: only instead of the 50 or so pages I imagined in said notebook(s), apparently upwards of 5000 pages have come down to us. With nothing in them about ANY protophotographic technique. Thank you, Clivedurdle.

Not true, as addressed above, but I would agree with you that the da Vanci' hypothesis is a stretch. Just because he is one of the few medevial clever guys who we can name doesn't mean that he is responsible for everything!

Quote:

4) Finally I should mention something else: (proto)photography as the source of the Shroud image is NOT a new idea. It began with the first photos taken of the Shroud in 1898. That's when it was noticed that the image was itself very like a film negative. However, for a host of historical (ie chronological), and technical reasons, this was all but abandoned in the late 20th Century.

One of the main reasons that hypothesis was rejected was the 3D quality of the image. Wilson's contribution is to explain how that could be reproduced. Again, one does not need high quality plate glass; artisans of that era were extremely skilled and clever at manipulating the small bits of glass that they could produce.

One of the arguments against stained glass (or glass at all) is that it was very expensive. True, but look at how many churches in even small communities had stained glass windows. In addition, there was a strong incentive for towns along pilgrimage routes to have relics; it could turn a backwater into a real tourist trap. Look at the Sword of Roland, the town of St. Andrews, or even the bizarre "brain of St. Peter" in the St. Gervais cathedral. Thousands of tourists would flock to the relics, they all needed a place to stay, a place to eat, perhaps a place to buy some knicknacks to take home....

Quote:

Wilson's 'contribution' is to 'resurrect'-------excuse the expression------this tired old nag for another trot around the track. He, like his uncritical supporters, apparently is largely ignorant of the vast body of scientific knowledge on what the full range of characteristics of the image is. Once again: see:Schwortz's paper, "Is the Shroud of Turin a Medieval Photograph? A Critical Examination of the Theory"

Schwortz's paper does not deal with Wilson's hypothesis, instead it deals with the shroud as a photographic plate in front of a camera with a fixed light source. Wilson's method answers all of the objections that I saw in a quick scan of the paper (sharp edges, lenses, dimensional encoding, chemicals.) What Wilson has done is explain the most puzzling aspect of the shroud, which is the apparent three-dimensionality of the image. This is pretty much the big hurdle, the rest is merely quibbling over details.

hw

S.C.Carlson · 03-28-2005, 08:09 PM

Quote:

Originally Posted by Happy Wonderer

One of the arguments against stained glass (or glass at all) is that it was very expensive.

More information about this aspect would be nice. I think it would be worth exploring whether other transparent or translucent materials, such as greased or wet paper/parchment, etc., could produce a similar effect.

leonarde · 03-28-2005, 08:47 PM

Quote:

Originally Posted by leonarde
1) I was not trying to convince or 'rebut' anyone. I was trying to supply information for those who <comment deleted> are genuinely interested in this subject.

I'm sorry if I wasn't clear, I was referring to the website as a rebuttal of Wilson's experiment. I'm not attacking you, in fact I am happy that you provided the website. The link I gave was from that website, you just had the front page and it took a bit of hunting to find what I wanted to discuss.

In fact in my immediately preceding post I linked TWO websites. It would help if in that situation you would indicate WHICH ONE (and if possible which PAGE) you are referring to (which you have still not done). I ASSUME you mean the second one(ie shroudstory) since that is the multi-page website.

Quote:

I addressed this. The absence of plate glass is a red herring, high quality stained glass windows have existed for a very long time.

But the purpose of 'stained glass' then, as now, was to depict scenes, frequently religiously-themed ones. It was DECORATIVE. It was NOT to direct light for photographic purposes (as far as we know based on the historical record). Even in the early-to-mid 19th Century, when we KNOW photography was feeling its sea legs, there were no instances (to my knowledge) of the pioneer photographers using stained glass of the medieval type.

The same evolution in quality of glass can be seen in the evolution of the microscope;

Quote:

A timeline covering the history of microscopes.
The definition of a microscope: An instrument for viewing objects that are too small to be seen easily by the naked eye.
Circa 1000AD – The first vision aid was invented (inventor unknown) called a reading stone. It was a glass sphere that magnified when laid on top of reading materials.
Circa 1284 - Italian, Salvino D'Armate is credited with inventing the first wearable eye glasses.
1590 – Two Dutch eye glass makers, Zaccharias Janssen and son Hans Janssen experimented with multiple lenses placed in a tube. The Janssens observed that viewed objects in front of the tube appeared greatly enlarged, creating both the forerunner of the compound microscope and the telescope.
1665 – English physicist, Robert Hooke looked at a sliver of cork through a microscope lens and noticed some "pores" or "cells" in it.
1674 – Anton van Leeuwenhoek built a simple microscope with only one lens to examine blood, yeast, insects and many other tiny objects. Leeuwenhoek was the first person to describe tiny cells and bacteria invented and he invented new methods for grinding and polishing microscope lenses that allowed for curvatures providing magnifications of up to 270 diameters, the best available lenses at that time.

(partial)
http://inventors.about.com/od/mstart...icroscopes.htm

Although I guess Hooke is generally credited with 'inventing' the microscope the process was obviously far longer and more laborious. But one cannot credit the 'first vision aid' of circa 1000 AD with the sharpness and clarity of later developments. And crediting 'stained glass' with the qualities necessary for photographic clarity and translucence, minus detailed information about same is, in my view, a mistake. Van Leeuwenhoek and others' success with the microscope was built largely on improving the grounding of lenses. It will NOT do to say that lenses existed way before van Leeuwenhoek, therefore (!!!!!) those predecessors could just as easily have done what he did.

But ANOTHER (in my view insuperable problem) with (all types of) photography as an image-making mechanism is: photography ALWAYS produces a left-right reversal; this is NOT the way the image of the Shroud is: it is without such a reversal....

Cheers!

Clivedurdle · 03-29-2005, 05:22 AM

Camera Obscura and Da Vinci

.National Museum Photography Film and Technology

Quote:

Camera Obscura

*

If a small hole is made in the window blind of a darkened room, an inverted image of the scene outside the window is produced on the opposite wall of the room. (The name Camera Obscura comes from the latin and means 'dark room'). This ability of a pinhole to form an image appears to have been known to the Ancient Chinese as early as the 4th century BC and was first described outside China by the Arabian scholar, Alhazen in about 1030.

A clear description of the formation of images by a small hole in a darkened room is contained in the manuscripts of Leonardo da Vinci in the fifteenth century and by the mid-sixteenth century, lenses had begun to be used to increase the brightness and sharpness of the image.

At first, camera obscuras were always a room in a house. By the seventeenth century, however, smaller, portable versions had appeared. Various forms evolved, including tents, sedan chairs and pocket models. Portable camera obscuras were used widely by artists as aids for sketching. For this purpose the most popular form was the reflex box camera obscura in which the lens formed an upright image on a sheet of translucent paper after reflection by an inclined mirror.

At the beginning of the nineteenth century, when the first photographic experiments were taking place, the camera obscura had evolved into three distinct forms; One form was a darkened room with a lens and mirror in the roof, producing an image on a table within the room. Such camera obscura were a common sight at seaside resorts and pleasure parks. A few examples survive today. A second type was in the form of a portable tent. A lens and mirror at the apex of the tent produced an image on a horizontal desk inside the tent. The third form was the portable box-form camera obscura which produced an image on translucent paper. It was this this type of camera obscura that eventually lead to the development of the photographic camera when it was used by the inventors of photography, Wedgwood, Niepce, Daguerre and Talbot.

Select bibliography
Coe, Brian, Cameras - From Daguerreotypes to Instant Pictures, Marshall Cavendish Editions, London, 1978, ISBN 0 85685 448 4
Hammond, John H, The Camera Obscura - A Chronicle , Adam Hilger Ltd, Bristol, 1981. ISBN 0-85274-451-X.
Scott, Peter, 'What Came First, Camera or Photograph?' in The Photographic Collector Vol 4 No 1, Spring, 1983 pp 90-105.

I wish there was a good summary of that National Geographic special somewhere, but it was pretty conclusive it was done by Da Vinci using camera obscura methods and early photo chemical methods. They discussed all these issues of reversal, 3D etc. If we use Occam's Razor here what do we have? Someone who loved these sorts of games, who understood all the important technologies. It should be quite easy using a computer to measure the details of the face to prove if it is Da Vinci or not - we can rebuild accurate faces from skulls.

03-28-2005, 04:17 PM	#26
leonarde Veteran Member Join Date: Mar 2002 Location: North America Posts: 1,603	In the interests of full disclosure I should mention that the unbiblical nature of the Shroud that spin sees is a perception shared by someone (page 4 points 1 and 2) at this website: http://www.letgodbetrue.com/bible/he...d-of-turin.pdf

Thread Tools	Search this Thread
Show Printable Version	Search this Thread: Advanced Search

03-28-2005, 03:13 PM	#23
leonarde Veteran Member Join Date: Mar 2002 Location: North America Posts: 1,603	I really have NO idea where you are coming from Vorkosigan. Are you claiming that flat glass existed in the 15th century???

Freethought & Rationalism Archive

The archives are read only.