The Shroud of Turin Mystery: The Molecule That Changed One Researcher’s Mind—and the Science That Challenged His Conclusion

For nearly two decades, Barrie Schwortz approached one of Christianity’s most controversial artifacts with a question he could not answer. A Jewish photographer who initially suspected the Shroud of Turin was a medieval forgery, he had examined its mysterious image, studied its unusual bloodstains, and worked alongside scientists searching for a credible explanation.

Then, during a telephone conversation in the mid-1990s, a fellow researcher introduced him to a molecule associated with a medical condition familiar to doctors around the world.

That molecule was bilirubin, a yellow-orange pigment produced when the body breaks down red blood cells.

For Schwortz, it appeared to solve one of the most troubling features of the shroud: why its reddish stains did not resemble the dark brown or black color commonly associated with aged blood. He came away from the conversation convinced that his final major objection had been answered.

But the story did not end there.

Later laboratory experiments challenged the explanation that had persuaded him. The scientific debate over the bloodstains continued, while questions about the cloth’s age, the formation of its image, and its historical origins remained unresolved.

The Shroud of Turin is therefore more than a religious relic or an enduring historical mystery. It is also a case study in forensic science, radiocarbon dating, chemical analysis, and the difficulty of distinguishing an intriguing explanation from one that has been conclusively demonstrated.

And at the center of the debate is a researcher whose journey began with skepticism.

The Jewish Photographer Who Almost Walked Away

When Schwortz became involved in the shroud investigation in the late 1970s, he did not expect the experience to change his life.

He was a technical photographer with professional training and a degree, preparing to work alongside specialists whose backgrounds included aerospace imaging, physics, chemistry, and government research. Several members of the scientific team had experience with organizations such as NASA’s Jet Propulsion Laboratory and Los Alamos.

To Schwortz, the project initially appeared to be an investigation of an object that was probably a medieval religious painting.

His own Jewish background made the situation feel even more complicated. He wondered whether he belonged on a project centered on an artifact associated with Jesus Christ and Christian belief.

He tried to withdraw from the team more than once.

One person who encouraged him to stay was Don Lynn, an imaging scientist at the Jet Propulsion Laboratory and a committed Catholic. Lynn reminded Schwortz that Jesus himself was Jewish and encouraged him to approach the investigation professionally rather than through assumptions about religion.

The message was straightforward: go to Turin, examine the evidence, and do the best work possible.

Schwortz agreed.

At the time, he could not have known that his photographs, scientific questions, and later educational work would become closely associated with the modern debate surrounding the shroud.

Turin, 1978: The First Surprise

The investigation faced logistical problems before the scientists could begin their work.

The team arrived in Italy ahead of schedule, bringing approximately 80 crates of equipment. Customs officials held the shipment for several days, creating uncertainty around an examination that had required extensive preparation.

The researchers had developed a detailed testing plan and originally hoped to spend 96 hours examining the cloth. Ultimately, they obtained roughly 120 hours, working in demanding conditions inside the royal palace beside Turin Cathedral.

When the linen was placed on an examination table, Schwortz looked for something familiar to a photographer: evidence of brushwork.

He expected that a close inspection might reveal strokes, pigment deposits, or other signs that an artist had created the image.

Instead, he could not identify the brushstrokes he had anticipated.

The image appeared unlike an ordinary painting, although that observation alone could not establish how it had been produced.

Another photographer on the team, Vern Miller, also examined the cloth. Both men paid particular attention to the reddish stains that appeared on the linen.

Those marks raised a different problem.

At first glance, Schwortz thought they looked unusual for blood. If the material really was blood, why did it appear so red?

That question remained with him long after the examination ended.

The distinction matters because the Shroud of Turin authenticity debate involves several separate questions. Establishing that an image does not resemble conventional brushwork would not, by itself, prove that the cloth dates to the time of Jesus. Nor would identifying a substance as blood establish whose blood it was or when it reached the linen.

Each claim requires its own evidence.

The Photograph That Turned a Negative Into a Positive Image

The shroud’s photographic history began decades before Schwortz arrived in Italy.

In May 1898, Turin marked the 400th anniversary of its cathedral, and the linen was displayed publicly. Secondo Pia, a lawyer and amateur photographer, received permission to photograph it.

The equipment available to photographers at the time was primitive by modern standards. Because the cathedral lacked electric lighting, Pia used a portable generator and lamps to illuminate the cloth.

Late on May 28, he developed his photographic plates.

What emerged surprised him.

In an ordinary photographic negative, light and dark areas are reversed. A portrait can consequently appear distorted or ghostly. But Pia’s negative seemed to reveal a much more natural-looking face, complete with closed eyes, a beard, and features that appeared bruised or swollen.

The discovery suggested that the image on the cloth behaved in a way that produced a positive-looking portrait when photographed as a negative.

Pia’s results were controversial. Critics questioned his photographic technique and accused him of manipulating the image. The allegations followed him for decades.

In 1931, another photographer, Giuseppe Enrie, photographed the shroud during a public display associated with a royal wedding. His photographs produced a similar result, helping to strengthen the case that Pia’s original images were not simply the product of a photographic mistake.

Yet photography could answer only part of the mystery.

A negative image may reveal something unusual about the distribution of light and dark on a surface. It cannot, by itself, identify the material responsible for those patterns or determine how they formed.

The shroud still required a scientific explanation.

The Three-Dimensional Puzzle

In the 1970s, researchers discovered another feature that made the shroud especially intriguing.

John Jackson and Eric Jumper, two scientists associated with the United States Air Force Academy, examined a photograph of the cloth using a device called the VP-8 Image Analyzer.

The machine converted variations in image brightness into a representation of height. In an ordinary photograph, brightness generally depends on lighting, shadows, and the properties of the photographed subject. The VP-8 instead treated the brightness values as depth information.

When the researchers processed the shroud image, a three-dimensional representation of the face emerged.

The nose, cheeks, and brow appeared in proportions that seemed more coherent than the distorted results produced when ordinary photographs were processed in the same way.

This finding helped motivate a more extensive scientific investigation.

However, the device did not prove that the image had been produced by a supernatural process. Its output depended on how brightness values were interpreted, and the meaning of the resulting three-dimensional pattern remains open to debate.

A later alternative explanation illustrates the difficulty.

In 2025, a study published in Archaeometry proposed that a shallow sculpted relief covered with cloth could reproduce important features of the shroud image more convincingly than fabric wrapped around a human body. The argument focused on how contact between a cloth and a three-dimensional surface could affect the resulting image.

Supporters of the shroud’s unusual characteristics disputed the interpretation.

The broader question remains whether the image’s characteristics can be explained through a known physical process, an artistic technique, or some combination of factors that has not yet been adequately reproduced.

For researchers, the science behind the Shroud of Turin is not one problem but a collection of related problems.

The Bloodstain Controversy

The question that troubled Schwortz most was the appearance of the red stains.

In 1980, microscopist Walter McCrone reported that sticky-tape samples taken from the cloth contained red ochre and vermilion, pigments historically associated with painting. He interpreted his findings as evidence that the shroud had been created by a medieval artist.

His conclusion challenged researchers who had found no obvious brushstrokes during their examination in Turin.

Other scientists reached a different interpretation.

Biophysicist John Heller and chemist Alan Adler conducted chemical analyses of samples from the shroud. They reported evidence consistent with hemoglobin, albumin, and other components associated with blood. Their findings appeared in the scientific literature in 1981.

Heller and Adler argued that the iron-containing material observed in the samples could be explained by blood rather than simply by an artist’s pigment.

The disagreement exposed a central difficulty in the investigation: identifying substances in tiny, historically handled samples is not the same as reconstructing the complete history of an artifact.

Different tests can detect different chemical features. Their results must be interpreted in light of the samples’ condition, possible contamination, and the limits of the methods used.

The dispute has continued to influence discussions of bloodstain analysis, historical textiles, and the reliability of conclusions drawn from limited physical evidence.

Another reported observation added to the debate.

Researchers examined fibers in areas where the bloodstains and body image appeared to overlap. Enzymatic treatment was used in an attempt to remove protein material from selected fibers, and the researchers reported that the underlying image-bearing fibers appeared unchanged.

They interpreted this as support for the possibility that the blood reached the cloth before the body image formed.

That interpretation has been debated, in part because the number and representativeness of the samples are important. Even if the sequence were established for a particular area, additional evidence would be required to determine the complete process by which the image formed.

The distinction is essential: a proposed sequence of events is not automatically proof of a specific origin.

What the Hand and Arm Stains Can—and Cannot—Tell Us

The shroud’s apparent wounds have also attracted attention from researchers interested in Roman crucifixion practices.

In many traditional religious paintings, nails are shown passing through the palms of Jesus’ hands. Schwortz and other advocates of the shroud have pointed to the apparent location of the hand wounds, which seem closer to the wrist than to the center of the palm.

They have argued that this positioning may be consistent with the practical demands of crucifixion.

However, the location of the marks cannot independently establish the identity of the person depicted. Nor does it settle the question of how the image was made.

In 2018, forensic anthropologist Matteo Borrini and a chemistry colleague published a bloodstain-pattern study in the Journal of Forensic Sciences. They examined photographs of the shroud and conducted experiments using volunteers, real blood, and synthetic blood.

The researchers concluded that some of the depicted flows were difficult to reconcile with a single body position. In particular, they questioned whether the patterns on the hands and back could all have formed as the result of the same sequence of events.

Critics of the study argued that the investigators did not directly examine the original linen and relied on photographs and experimental models. They also questioned whether the experimental conditions adequately represented the circumstances that the shroud’s defenders proposed.

The disagreement highlights a broader principle in forensic bloodstain pattern analysis: investigators must account for body position, gravity, the properties of the liquid, contact with surfaces, and the conditions under which stains formed.

A stain can be consistent with one explanation without uniquely proving it. Equally, a mismatch in a reconstruction may challenge a theory without resolving every aspect of the case.

The shroud’s bloodstains remain disputed evidence rather than a universally accepted solution.

DNA and Dust: A Journey Through Centuries of Contact

The linen has been handled, displayed, repaired, and transported over many centuries. That history complicates attempts to determine its origins through biological material.

In 2015, a team led by geneticist Gianni Barcaccia at the University of Padua published an analysis of DNA recovered from particles collected from the back of the shroud.

The researchers detected genetic material associated with humans and plants. The human DNA included lineages associated with several regions, while the plant material reflected a similarly varied collection of sources.

Some plant DNA came from species that reached Europe after the medieval period, including plants native to the Americas. This was not necessarily evidence that the linen itself originated in those regions. It could instead reflect later contact, handling, or contamination.

The authors cautioned that the genetic mixture did not rule out a medieval European origin. They also noted that the results were compatible with a more complicated history involving contact with people and materials from the Near East and other regions.

Other analyses of historical samples have reported unusual plant DNA, including material associated with carrots. Some researchers have suggested that such findings might be relevant to the history of the linen or its manufacture.

But DNA recovered from a frequently handled artifact cannot automatically be treated as a reliable map of its original birthplace.

Ancient DNA analysis is particularly sensitive to contamination, the age and condition of samples, and the distinction between material belonging to an object and material deposited on it later.

The shroud’s genetic traces therefore offer clues about its history of contact, but they do not establish that it was present in Jerusalem during the first century.

The Radiocarbon Test That Changed the Debate

By the late 1980s, scientific interest in the shroud had grown considerably. One question appeared capable of producing a more direct answer than many of the debates over its image: how old was the linen?

In 1988, small pieces were cut from a corner of the cloth and distributed to three laboratories: the University of Oxford, the University of Zurich, and the University of Arizona.

The laboratories used radiocarbon dating, a method that estimates the age of organic material by measuring the remaining radioactive carbon-14.

In February 1989, the results were published in the journal Nature. The reported date range was approximately 1260 to 1390, with a stated confidence level of 95 percent.

The authors concluded that the tested linen dated to the medieval period.

The result was a major turning point. If the tested material reliably represented the shroud as a whole, it would rule out the claim that the linen itself was a first-century burial cloth.

The historical record also supported a medieval context.

The shroud appears clearly in European documentation in the 1350s, when it was associated with a church in Lirey, France, founded by Geoffroi de Charny. Pilgrims visited the site, and surviving medieval objects depict a long cloth bearing a double image.

In 1389, Pierre d’Arcis, the local bishop, wrote a memorandum alleging that the cloth had been cleverly painted and that an unnamed artist had confessed. The account is important historical evidence, although the alleged confession has not been independently established.

In 2025, historian Nicolas Sarzeaud brought renewed attention to a passage by the French philosopher Nicole Oresme, written around 1370. The passage referred to a church claiming to possess the Lord’s shroud as an example of religious deception.

The interpretation and significance of that passage have been discussed by historians. Nevertheless, it adds to the evidence that doubts about the shroud’s authenticity existed during the medieval period.

Taken together, the historical documentation and radiocarbon result provide substantial support for a medieval origin. But researchers have continued to debate whether the dated sample was fully representative of the entire cloth.

Why Some Researchers Question the Date

The radiocarbon result has not been universally accepted by advocates of an older origin.

In 2005, chemist Raymond Rogers, who had participated in the original research effort, published an analysis arguing that the dated corner contained material different from the main body of the linen. He suggested that the area might have been affected by a medieval repair involving cotton and other substances.

If the tested corner had been repaired, the argument goes, the measured date might not accurately represent the age of the original cloth.

Other researchers disputed that interpretation.

In 2010, scientists associated with the University of Arizona examined a remaining piece of the radiocarbon sample and reported that they found no evidence of the coatings, dyes, or other features that Rogers had proposed. They concluded that the material appeared consistent with the main cloth.

The competing analyses remain part of the scientific discussion.

Another challenge concerned the statistical treatment of the original measurements.

In 2019, Tristan Casabianca and colleagues published an analysis in Archaeometry after obtaining previously unavailable radiocarbon data. They argued that the measurements showed variation that warranted further examination and questioned whether the original published analysis fully captured the uncertainty.

Their argument did not establish that the shroud was older than the reported date. Rather, it called for caution in treating the result as conclusive for every part of the linen.

That distinction is important. Questioning the reliability or representativeness of a sample does not automatically validate an alternative date.

The most direct way to address the dispute would be through additional testing using carefully selected samples, transparent methods, and independent scrutiny. However, any new sampling would need to balance scientific value against the preservation of an object regarded by many people as an irreplaceable religious artifact.

For now, the medieval date remains the best-established published radiocarbon result, while questions about sampling and statistical interpretation continue to be debated.

The Image That No Laboratory Has Fully Explained

Even if the linen’s date is accepted, another question remains: how was the body image produced?

Studies have reported that the yellow-brown discoloration associated with the image is concentrated in an extremely thin surface layer of the linen fibers. This characteristic has made it difficult to reproduce the image through ordinary painting or other simple techniques.

In 2011, physicist Paolo Di Lazzaro and colleagues at ENEA, Italy’s national energy agency, reported experiments involving very short ultraviolet laser pulses. Under controlled laboratory conditions, the researchers produced localized discoloration in linen resembling some aspects of the shroud’s image.

Their work demonstrated that intense ultraviolet radiation can create certain image-like effects on linen. But the experiments did not reproduce a complete, full-sized human image with all the shroud’s reported characteristics.

The team estimated that producing the entire image through the same approach would require an extraordinary amount of ultraviolet energy, beyond the capabilities of available sources at the time.

That result does not prove that the shroud’s image was created by ultraviolet radiation. It instead illustrates how difficult it is to reproduce the complete pattern through one proposed mechanism.

Researchers have considered several possibilities, including chemical reactions, thermal effects, contact processes, and artistic methods. Each explanation must account for the image’s distribution across the cloth, its superficial coloration, and the relationship between the image and the stains.

A convincing theory would need to explain the observations together rather than addressing only one unusual feature.

That is why the Shroud of Turin scientific investigation remains unresolved despite decades of research.

Two Fires That Nearly Destroyed the Evidence

The shroud’s physical condition has also shaped the investigation.

On December 3, 1532, a fire broke out in the Sainte-Chapelle in Chambéry, France, where the linen was kept folded inside a container. The heat damaged one corner of the cloth and left a pattern of holes.

In 1534, Poor Clare nuns in Chambéry sewed patches over much of the damaged area. These repairs remained attached to the shroud for centuries.

During restoration work in 2002, textile specialists removed the historic patches, allowing closer examination of the reverse side of the linen.

The back revealed additional details, including areas associated with the bloodstains. Researchers have emphasized the absence of a corresponding body image on the reverse, although the significance of this observation depends on the proposed mechanism of image formation.

A second fire threatened the shroud on April 11, 1997, when flames spread through the Guarini Chapel in Turin.

Fortunately, restoration work had led to the cloth being stored elsewhere in the cathedral complex. Firefighters worked to reach the reliquary protected behind heavy glass.

One firefighter, Mario Trematore, became widely associated with the rescue after using a sledgehammer to break through the protective barrier. He helped remove the reliquary before the fire could destroy the artifact.

The episode became part of the shroud’s modern history, reinforcing the sense that its survival has been precarious.

From a conservation perspective, the fires also explain why researchers must work carefully with limited samples and why proposals for additional testing can be difficult to implement.

The Phone Call About Bilirubin

The question that had troubled Schwortz since 1978 finally came up during a telephone conversation with Alan Adler in the mid-1990s.

Adler was a chemist who had investigated the shroud’s bloodstains. Schwortz explained that the color of the stains remained a major obstacle to his acceptance of the evidence.

Why did the marks look so red?

Adler discussed bilirubin, a pigment that forms during the breakdown of hemoglobin. Bilirubin levels can rise significantly under certain medical conditions, including severe illness and some forms of jaundice.

Adler proposed that elevated bilirubin in the blood of a severely injured person might help explain the unusual color of the shroud’s stains.

The suggestion was appealing because it offered a possible chemical explanation for a feature that Schwortz had struggled to reconcile with the claim that the stains were genuine blood.

In Schwortz’s account of the conversation, Adler presented the idea as an answer to his remaining objection. Schwortz came away convinced that the blood’s color no longer prevented him from accepting the shroud as authentic.

The molecule that changed his mind was not an exotic substance or a mysterious chemical. It was a familiar product of the body’s own biology.

But an important scientific distinction separates a plausible explanation from a demonstrated one.

The presence of bilirubin in blood does not, by itself, establish how a particular stain will look after centuries on linen. The color of a historical bloodstain can be affected by oxygen, temperature, humidity, the surrounding material, exposure to light, and other chemical processes.

To establish Adler’s proposal, researchers would need to reproduce the relevant conditions and demonstrate that the resulting stains reliably match the characteristics being explained.

That question would soon receive closer scrutiny.

The Experiment That Challenged Schwortz’s Conclusion

In later years, immunologist Kelly Kearse investigated the bilirubin explanation through experiments involving blood and fabric.

Kearse reported adding bilirubin to fresh human blood at a concentration far above ordinary levels and allowing the resulting stains to age. He also explored different chemical forms and concentrations of bilirubin, along with blood from animals bred to have unusually high bilirubin levels.

According to his published accounts, the stains generally darkened rather than maintaining the persistent red appearance that the hypothesis was intended to explain.

Kearse also examined an alternative idea associated with Rogers: that treatment with soapwort, a plant historically used in textile processing, might influence the color of blood on linen.

In his experiments, soapwort-treated fabric did not preserve the reddish color as expected.

The work challenged the idea that bilirubin alone could account for the shroud’s bloodstains. It did not, however, determine the stains’ actual origin.

Kearse also reported an unexpected observation: blood on fabric treated with glycerin retained a reddish appearance for a period before darkening. He suggested that this finding might have practical implications for some forensic investigations involving bloodstained materials.

That observation is separate from the question of the shroud’s authenticity. A result involving recently prepared fabric cannot establish the history of a centuries-old textile without further evidence.

Other research has explored whether ultraviolet exposure might affect the color of blood containing elevated bilirubin. A 2018 paper in Applied Optics reported color changes under particular experimental conditions, adding another variable to the debate.

The overall picture is complicated.

Adler’s explanation helped persuade Schwortz, but later experiments did not establish that bilirubin could preserve the shroud’s reddish stains in the way the hypothesis required. Other chemical and environmental factors may be relevant, and the precise cause remains unconfirmed.

The episode illustrates a central principle of scientific testing and evidence evaluation: an explanation can be reasonable enough to investigate without being sufficiently demonstrated to settle a historical question.

Did the Shroud’s Photographer Become Too Convinced?

Schwortz’s decision to accept the shroud as authentic was personal, but his public position included an important qualification.

He did not claim that a scientific investigation could prove the Resurrection. He argued that the evidence should be considered as a whole and that individual observations needed to be evaluated in the context of the larger picture.

That approach can be useful, provided the evidence is weighed carefully.

A collection of unresolved questions does not automatically establish a preferred explanation. The absence of an accepted mechanism for the image, for example, does not prove that the cloth is first-century. Likewise, criticism of a radiocarbon sample does not establish a different date.

The same caution applies to the bloodstains. Even if future testing establishes that some stains contain genuine blood, that result alone would not identify the person involved or prove the circumstances under which the cloth was used.

Schwortz’s contribution was not that his personal conclusion ended the debate. It was that his photographic work and continued interest helped make the shroud’s scientific questions accessible to a much wider audience.

He later established Shroud.com, an online resource devoted to information about the cloth, and continued to lecture and discuss the investigation. The website became a reference point for people seeking photographs, research summaries, and historical material.

Schwortz died in June 2024, almost 46 years after his first close examination of the linen in Turin.

His story remains compelling because he began with skepticism, encountered evidence he found difficult to explain, and changed his mind. Yet his experience also demonstrates why scientific conclusions must remain open to reassessment when new experiments challenge an earlier interpretation.

What the Evidence Actually Tells Us Today

The Shroud of Turin occupies an unusual position between religious devotion, historical documentation, and scientific investigation.

Its image has characteristics that have attracted sustained scientific attention. The photographic negative effect, the apparent depth information, and the thin surface discoloration are legitimate subjects for study. They are not, on their own, proof of a miraculous origin.

The bloodstains have produced competing chemical interpretations. Some researchers have reported evidence consistent with blood components, while others have argued for pigments or questioned the interpretation of the patterns. The bilirubin explanation that influenced Schwortz has not been conclusively established.

The radiocarbon test published in 1989 placed the sampled linen between 1260 and 1390. Later researchers raised questions about the sample and statistical analysis, but those objections have not established a verified first-century date. The surviving historical record places the shroud securely in European accounts during the medieval period.

DNA and plant traces reveal that the cloth has had a complex history of contact, but contamination and centuries of handling make it difficult to use those traces to establish its original location.

Finally, no proposed physical process has been universally accepted as a complete explanation for every characteristic of the image.

These conclusions may disappoint anyone hoping for a definitive verdict. But uncertainty is not a failure of science. It is an honest description of what the available evidence can and cannot establish.

The Question Schwortz Left Behind

The most striking part of Schwortz’s story is not simply that a molecule changed his mind. It is that the explanation that persuaded him later became the subject of experiments that challenged it.

That does not make his original skepticism meaningless, nor does it mean that his final conclusion was deliberately dishonest. It shows how scientific understanding develops: researchers form hypotheses, test them, discover limitations, and revise their interpretations when the evidence demands it.

The shroud’s supporters may see its unusual characteristics as evidence of a remarkable origin. Skeptics may see the medieval documentation and radiocarbon result as strong reasons to reject a first-century attribution. Other researchers continue to investigate the chemical, physical, and historical questions without claiming to have settled the matter.

The responsible conclusion is that the Shroud of Turin remains a disputed artifact whose full history and image formation have not been conclusively explained.

Schwortz spent decades examining the evidence and encouraging people to make up their own minds. His legacy is best served not by treating his personal conviction as the final word, but by continuing to investigate the questions that first drew him to the cloth.

The bilirubin puzzle remains a reminder that even a promising scientific explanation must survive testing.

And until the evidence provides stronger answers, the most useful question is not whether one researcher was finally convinced. It is whether the explanations offered for the shroud can withstand the same scrutiny that made the mystery worth investigating in the first place.