taken from this website: http://www.skepticalspectacle.com/

"The thoughtful skeptical inquirer's highest aim is not to achieve this or that outcome for something controversial. Rather, the thoughtful skeptical inquirer honors the process of careful reasoning.

Imagine slicing a human hair lengthwise, from end to end, into 100 long thin slices, each slice one-tenth the width of a single red blood cell. The images on the Shroud, at their thickest, are this thin. The faint images, golden-brownish, formed by a caramel-like substance, are wholly part of a super-thin film of starch fractions and sugars. Where this film is not brown, it is clear.  Knowing the way certain ancient linen was made, the film covering on just some of the cloth's fibers can be expected. And knowing that dead bodies produce gaseous cadaverine and putrescine that react with sugars to form caramel-like substances called melanoidins, the color is not only possible, it is expected: Strange coatings of saccharides turned brown. Spectral data, chemical tests and photomicrographs show that this is so. All this is documented in secular peer-reviewed scientific journals. The honest skeptical inquirer must wonder, How can this be?
It is preposterous to think the Shroud of Turin was painted.

The notion that such super-thin images were painted is preposterous. Yes, it is true that one scientist did look through a microscope and find components of what might have been paint. And because of this he concluded that the Shroud was painted. Walter McCrone was a world-renowned microscopist, deservedly so. He was a true scientist and he knew his craft well. We should not doubt that he found iron-oxide and mercury-sulfide, both constituents of paint. But there are many reasons why such chemical particles might be found on the Shroud. Water used for retting flax introduced iron. And centuries of dust, particularly dust in churches with frescoed ceiling and walls, introduced all manner of trace contaminants. All other scientists who examined the image fibers -- many of them every bit as renowned and qualified -- have disagreed with McCrone. There is, simply, an insufficient amount of paint constituents to form a visible image. Spectral analysis proves that. So does the now certain knowledge of the image bearing super-thin film. Ironically, McCrone identified the super-thin starch substance that ultimately became part of the proof that his conclusions were wrong.

So what are we to make of a 14th century bishop, Pierre d'Arcis, who wrote in a memorandum that a painter confessed to painting the Shroud's images? In isolation his document is damning. But the skeptical inquirer, being true to his ways, must challenge such a claim with the full conspectus of what was being written at the time. Pierre's peers doubted his veracity and questioned his motives. It was all about money. Pierre was the bishop of Troyes. The Shroud was being exhibited at nearby Lirey; and it was to that town that pilgrims with bags of coins were flocking. The d'Arcis memorandum is pointless. The skeptical inquirer is fully justified in his skepticism; for no painter painted on a caramel substance and a surrounding clear substance that was a hundred times thinner than a single brush hair.
The carbon 14 dating sample from the Shroud of Turin was invalid.

Did not carbon 14 demonstrate that the Shroud was medieval? Could it possibly be wrong? Carbon 14 dating, the skeptical inquirer knows, is useful for dating material going back about 50,000 years. And it is extraordinarily accurate for material less than 10,000 years old. Yes, there can be problems with contamination. But the labs that do this work do a very good job of removing contamination with combinations of alkaline and acidic baths. And yes, absolute precision is impossible. In the Shroud carbon 14 samples there was less than one carbon 14 atom for every trillion or so carbon 12 and carbon 13 atoms. But the quantity of material was sufficient and the methods accurate enough to estimate that the material tested produced a statistically certain range of dates: 1260 to 1390 CE. Even so, there might be a reason to suspect some error.

There have been claims that a biological polymer was growing on the Shroud and that this could have affected the date. Not so! The National Science Foundation Mass Spectrometry Center of Excellence at the University of Nebraska, using highly sensitive pyrolysis-mass-spectrometry, could not detect any such polymers on Shroud fibers.  Furthermore, it is well known that a biopolymer product would show the same carbon age as the Shroud because the organism would use fixed carbon from the cellulose fibers and not from the atmosphere. Similar claims that a scorching fire in 1532 might have altered the carbon 14 isotope ratios are scientifically unsustainable. The skeptical inquirer is right to pooh-pooh such ideas.

But as the skeptical inquirer knows, material intrusion is a potential problem in carbon 14 dating. A classic example is the dating of peat from ancient bogs. Miniscule roots from much newer plants get entangled in the peat -- some roots having decomposed into newer peat -- and this will distort the results. Could something like this have affected the results of dating of the Shroud? As it turns out, chemical and visual analyses, done in just the last two years, show unmistakable proof of material intrusion of new linen fibers -- enough material by some estimates to make a 1st century cloth seem medieval. The discovery of alizarin dyes (from Madder root), a hydrous aluminum oxide mordant and plant gum along with twisted-in cotton fibers and spliced threads in the carbon 14 sample region shows that the sample area was discretely repaired. These substances are not found anywhere else on the Shroud. Shroud of Turin Story Breaking News
Other recent findings about the Shroud of Turin are intriguing.

The skeptical inquirer knows about decomposition kinetics. He knows that the cloth is linen. Each thread of the cloth is made up of roughly a hundred fibers from a flax plant. The skeptical inquirer knows about lignin, a complex polymer compound, one of the constituents of flax fibers. He knows that lignin's chemical composition changes over time. He knows that if a microchemical test for vanillin in lignin is negative that the cloth is more than 1300 years old, twice the age that the carbon 14 dating estimated. Clues from vanillin showed something was wrong in the carbon 14 tests. Something was very wrong.
The second face on the Shroud of Turin.

In 2004, a startling discovery was made. A faint second face was found on the back of the Shroud. This second face was directly behind the face on the front of the cloth as though paint or stain had soaked through. But when we probe between the two facial images, when we look at the interior of the threads, when we examine individual fibers, we discover that nothing has soaked through. The faces are thin and superficial to the extreme outer surfaces of the Shroud.
History weighs to support a very early Middle East provenance for the Shroud.

Whatever the Shroud of Turin is, it is not a painted, medieval fake-relic. The unmistakable images of a crucified man were not created by any known artistic method. And thus, the honest skeptical inquirer will turn to history for clues. In doing so he discovers that newly found, newly translated and newly interpreted documents provide a plausible historical scenario for something that is not a medieval fake-relic.

Almost certainly, an image-bearing piece of cloth taken from Edessa in 944 by the armed forces of the Byzantine Emperor, a cloth described on that occasion by Gregory Referendarius, the archdeacon of Hagia Sophia, is the Shroud of Turin. This image-bearing cloth disappeared from Constantinople in 1204 in the hands of French crusaders. We can trace it to Athens in 1207. But there the trail grows cold. If the Edessa Cloth -- later in Constantinople called the Holy Mandylion -- is indeed the Shroud, it reemerges in the annals of history in Lirey about 1355. The gap of about 150 years is uncomfortable. But such gaps are not unusual in the pursuit of history. It is in the plumbing and searching for details that historians find connections that bridge historical gaps; all too common gaps in ancient history. The description by Gregory, a drawing from the late 1100s, tantalizing clues sifted from commonly redacted and exaggerated legends and letters, and citations from documents that no longer exist: these things are plausible.

It may have ended up in Besançon. There is some reason to think so. There is good reason to believe it was acquired by the French knight, Geoffrey de Charny by 1349 but not much earlier. We know, without any doubt, that it was displayed in Lirey just before Geoffrey was killed at the Battle of Poitiers. And there is no doubt, whatsoever, that cloth displayed in Lirey is the cloth that now resides in Turin.

Botched carbon 14 dating, images formed by the caramel-like substance, a plausible history that tracks back to the 6th century while suggesting an earlier provenance: all that is undeniable. But is that enough? Is the Shroud of Turin the genuine burial shroud of the historical Jesus as millions believe? While the evidence is good, it is not conclusive.
Some claims in support of the Shroud of Turin's authenticity are dubious.

Some claims, sometimes presented to try and establish the cloth's authenticity, are just not evidentiary. For instance, claims of barely perceptible images of Roman lepta coins over the eyes of the man are flimsy and so far lack scientific confirmation. And speculation, sometimes touted as theory, that the images were formed by radiation released from a miraculous resurrection event, is scientifically preposterous. We need not debate resurrection or cerebrate on the physical nature of a miraculous resurrection. That work belongs to philosophers who might wonder if God, in performing miracles, might leave bits of sub-atomic particles lying about in all the right places, in just the right measures, at just the right time, to imprint, on purpose or by accident, an image on the cloth?

Radiation, almost certainly, could not have formed the caramel-like substance that makes up the images: not electromagnetic radiation; not ionizing particles such as protons, electrons, and alpha particles; and not non-ionizing particles such as neutrons. Enough energy to induce a chemical change in the super-thin film that holds the image would have visibly altered the characteristic molecular arrangement, the fibrillar structure of the flax fibers. That did not happen.

In the historical context, some evidence is dubious. That the Shroud may have been the hands of the Knights Templar; or the Cathars (the Albigensians) in Languedoc or in Greece or hidden away in Constantinople, as some have proposed, are at best only possibilities. Possibilities don't close gaps and don't make for good history. The skeptical inquirer is right to question such arguments. But he is not right to assume that gaps mean there is no history.
It is the face on the Shroud of Turin that intrigues us the most.

The Shroud is a fourteen foot long piece of linen cloth. On one half of its length (the lower half in the accompanying picture), there is a frontal image of a man from head to foot. On the other half, upside down as though standing on his head, is an image of the man's backside. We can clearly see the shape of the man's head, torso and legs. We notice that his arms are before him and crossed at the wrists. If we look carefully, we can see features of the man's face: his eyes, his nose, his mustache and beard.

It is that face that is the most intriguing issue for the skeptical inquirer. There is something in the passionate exactness of the picture, something of a sleight-of-hand quality that resonates with whatever we believe. The picture is quite astounding. To the unquestioning believer in the Shroud's authenticity, it is not an image made by the hand of an artist: God made the image or it is an unlikely accident of nature. On the other hand, the  hardened skeptic, both the atheist and the miracle-eschewing believer in God, cannot help but believe that the images are faked. He is skeptical of the Shroud just as the creationist-fundamentalist is skeptical about the evolution of the earth and its creatures: each in his own way must reject the conclusions of science and history. It is to the honest skeptical inquirer, whether motivated by faith in the unexplained or by doubt born of modern sensibilities, that the quest for elusive truth belongs.

The skeptical inquirer knows well that the familiar face, the so photorealistic face that astounds, is not the face that is actually on the Shroud. The face on the Shroud is bleary, ghostlike picture. It looks something like a soaked-in, blurred stain. However, when the Shroud of Turin is photographed --  something that happened for the first time in 1898 -- a startling image emerges on the photographer's film. The image on the negative, on the film, is a positive picture. That can only be so if the images on the Shroud are, themselves, negative images. What can that mean?

Are we to imagine, in an age before photography was invented, before anyone saw a photographic negative, that someone would or could create images like those on the Shroud? Why? How so, without an example of a continuous-tone, grayscale negative? Without a camera and film, how would an artisan know that he got it right? Perhaps, we might think, it was an accident. But surely, that is as improbable as Jackson Pollock dribbling paint onto a canvas from atop his twelve foot ladder and accidentally producing a perfect replica of the Mona Lisa.
There are plentiful odd qualities in the Shroud of Turin images.

Why does a computer plot of the image's color density produce a 3D terrain map, an inexplicable 3D optical illusion phenomenon? No pictorial work of art does so; nor does a photograph. Why can't you see the image if you stand very close to it? It really isn't a mystery; but it is very telling about the image. Why does the man look so gaunt? In reality, the image isn't of a narrow face. An optical illusion caused by the way the cloth was bleached makes us see the man as having a very thin face.

And why is the blood of the bloodstains red? It really is blood. That has been proven over and over by many scientists working independently of one another. Old blood normally turns black. The reasons it is red are simple. Ancient cloth, as it was manufactured in the the Middle East during the first century, was starched on the loom and then washed in suds of the Soapwort plant. Ingredients of this natural soap are hemolytic, which would keep the blood red. We know, as well, that the blood on the Shroud is rich in bilirubin, a bile pigment produced when a human body is under severe traumatic stress. Bilirubin is bright red and stays red.

The biggest mystery of all is if the Shroud of Turin is a grave cloth, which is something that we might infer, then how is it that it survived the grave? Why did it not rot away? Why are there no signs of decomposition fluids that would occur within about three days? Why, indeed, was it separated from the body it covered?

This photo-rich website addresses many of these issues. It is organized like a museum website. Select a general topic, click on thumbnail picture, and browse through the dozens of pictures and the captions. Bookmark the site and visit often.

The true skeptical inquirer should not be confused with the magazine, Skeptical Inquirer. The Skeptical Inquirer is the journal of CSICOP, the "Committee for the Scientific Investigation of Claims of the Paranormal," an organization that has included such scientific luminaries as Carl Sagan and Steven Jay Gould.

Skeptical Inquirer is an interesting and entertaining magazine. It usually does an excellent job of debunking outlandish myths, urban legends and all manner of unscientific claims. But when it comes to the Shroud of Turin it has failed. For the editors of Skeptical Inquirer, everything they find distasteful in religion and Christianity is mimicked in pitiable fashion as they struggle to attack the Shroud's authenticity. They recast history to their own fancy. They ignore scientific facts unless they suits their purpose. Hilariously, without any sense of exegetical perception, they cite the "Christian Bible," as though they thought the text literally true, to argue that the Shroud of Turin is not authentic.

Were they honest to the principles of skeptical inquiry, the magazine would question the carbon 14 dating. As it is, in their failing, they will leave that to ethical, peer-reviewed, scientific journals. They would be skeptical of Walter McCrone. They would wonder why, of all the scientists who directly examined Shroud fibers, only Walter McCrone claimed to find paint. How is that possible if the documented, accessible, peer-reviewed spectral analysis proves otherwise? Why is it that McCrone's work cannot be reproduced by anyone? Why is it that he did not submit his work to peer review in the normal way that scientists announce their findings?

The Skeptical Inquirer magazine, with a series of articles by Joe Nickell has fooled itself by not being an inquirer and not being truly skeptical; for skepticism fueled by selective use of information is not skepticism at all. "