This may be the biggest mistake in modern Shroud research: believing that 3D data is encoded into the image in such a way that it eliminates photography and painting as possible mechanisms of its creation. Now presented as compelling evidence of authenticity—intended to reinforce the idea that the image formed as the cloth lay directly over a real human body—this claim has been echoed by organizations such as the Sign From God Foundation, which asserts:
Facts: The Shroud contains 3D “distance information,” the application of which was utilized as the basis for the History Channel’s 2010 mega-hit documentary “The Real Face of Jesus?” and 2017’s updated version, “The Face of Jesus Uncovered?” (No longer available from the History Channel)
This so-called “fact” requires serious scrutiny on three fronts: the nature of the data, the logic of inference, and the rhetorical use of popular media as validation.
A Notion of 3D Data in the Image
In 1976, physicist John Jackson and radiographic expert William Mottern ran a photograph of the Shroud through a VP-8 Image Analyzer, a device that creates 3D visualizations from grayscale images. Their conclusion, echoed in STURP’s 1981 official summary, stated:
The computer image enhancement and analysis conducted by a device known as a VP-8 image analyzer reveal that the image contains unique, three-dimensional information encoded within it.
Over time, this became a central talking point among Shroud advocates. In public presentations, Barrie Schwortz described the output as a “rather amazing natural relief of a human form,” implying that this distinguished the image from regular photographs or artwork. Eventually, Schwortz stated this to a wide audience:
This spatial data encoded into the image actually eliminates photography and painting as the possible mechanism for its creation and allows us to conclude that the image was formed while the cloth was draped over an actual human body.
(National Catholic Review, July 4, 2015)
That conclusion is simply not supported by the technology. The VP-8 is not a depth scanner. It interprets brightness—grayscale values—as height. Any image that behaves like a “heightmap” (a common topographic technique) will produce a 3D-looking surface. It does not follow that the image is encoded with actual spatial depth or contains “distance information” in the physical sense, any more than, say, we might think that an orange ball is necessarily an orange fruit.
As Ray Rogers pointed out, a drop of ink on porous filter paper will produce a “mountain” when processed by the VP-8. This is an illusion, not height or depth or “distance information.” It’s akin to plotting population density as terrain where densely populated cities seem like mountains while rural areas, be they mountains or swampy lowlands, appear as flat plains: The data maps into shapes, but the shapes aren’t physically real.
The VP-8 shows us apparent relief, not real relief. It is physically not able to do more than that. The word “apparent” is crucial, and it was regrettably omitted from the 1981 STURP summary and from public discussion and papers that followed.
The VP-8 Duck Test
The danger here is a classic essentialist fallacy—mistaking appearance for essence. The VP-8 image “looks” like a face with contours. Therefore, it must contain 3D data from a real body. It’s the duck test: if it looks like a duck, walks like a duck, and quacks like a duck, it must be a duck. But as philosophers like Karl Popper have reminded us, that’s not science—it’s presumption.
Groucho Marx, Monty Python, and Mark Twain all satirized this thinking. What looked like a real duck might be a rubber duck, a mirage, or a miraculous apparition of a duck. Or in this case, it might be a result of image-processing algorithms interpreting grayscale values, not encoded spatial data stemming from a miraculous event.
Other studies underscore this. In 1994, Drs. Emily Craig and Randall Bresee showed that by daubing powdered pigment onto cloth, they could create an image that, when plotted in 3D software, produced a human relief nearly indistinguishable from the Shroud.
Hugh Farey later pointed to experiments by Colin Berry, who used thermal imprinting to create “negative” images with 3D characteristics. Farey noted:
[Berry] demonstrated that almost any scorch will produce both an effective ‘negative’ image, and can be converted into a ‘3D image’ using similar software to that of the famous VP-8 Image Analyser, demolishing any miraculist claim that only the Shroud was capable of such effects.”
(British Society for the Turin Shroud Newsletter, June 2015)
While reviewing various image formation theories, I came across a proposal by Joseph S. Accetta, an original member of the STURP team, who suggested that a woodblock or intaglio technique—both known to have been in use in the 14th century—could account for all visible attributes of the Shroud image, including its apparent 3D characteristics. Intrigued, I tested the idea myself. Within half an hour of searching Google, I located a full-frontal woodblock portrait, and in about 15 minutes more, using Microsoft’s 3D Builder, I rendered it in simulated relief. The results were visually compelling and raised new questions about the assumptions often made regarding the uniqueness of the Shroud’s so-called “encoded spatial data.”
Accetta also pointed to a common photograph of a sculpted death mask—an ordinary flat image of a molded face—as another example likely to yield a comparable result when processed. He was right. When Colin Berry independently plotted this, the outcome again mirrored the so-called “encoded spatial data” effect. These simple experiments challenge the persistent narrative that the Shroud image alone can produce such 3D characteristics and suggest that the illusion may lie not in the cloth, but in our lack of experiments—and our jump-to-conclusion interpretations.
The Documentary Fallacy: Popularity ≠ Proof
The final piece of the puzzle is rhetorical. The Sign From God Foundation points to The Real Face of Jesus? as if its popularity lends scientific credibility. Even if it was a “mega-hit” (a debatable claim), that’s no substitute for empirical rigor. The rendering of a face from grayscale data is an artistic interpretation, not a forensic revelation. Artists do this all the time—from skull reconstructions to CGI-enhanced portraits. It proves creativity, not divinity.
Conclusion: The Weight of Apparency
It’s entirely reasonable to be intrigued by the Shroud’s VP-8 output. Many of us once were. But interest must not harden into certitude without clear, reproducible evidence. The VP-8’s output suggests a visual illusion of depth, not encoded spatial data. And from that, we cannot reliably leap to conclusions about authenticity or miraculous image formation.
As Twain might say, what we were so sure of, “just twasn’t so.” The Shroud’s image may look 3D, but appearances are deceiving—and when those appearances are used to manufacture theological certainty, we risk confusing suggestion for truth, and wonder for fact.
Hi, Dan,
Permit me to offer up “Not Good #5: The dark souls of men that devote themselves to attacking the cloth that contains Jesus’ atoning blood and His body image.”
You are fighting as cowards fight with this string of attacks when you know that, right now, Shroud scholars are extraordinarily busy preparing for the upcoming conference, and we do not have the spare time to deal with the numerous points that you raise in these ongoing attacks (which probably all of them have been previously discussed on your blog ad nauseam.) I, and others, have too many projects right now to get ensnared in your effort to derail our work by spending lots of time going through all of your points and getting caught up in endless discussions back and forth.
These attacks of yours smack of the frenzied desperation that Evil experiences in the presence of that which is Good and Holy. Undoubtedly, we will expect to see even more of your frenzied, desperate attacks in the coming days.
In the meantime, for people who want to see some curated highlights that I have personally authored and which cite to where people can specifically see what STURP has mentioned please see my recently published paper at https://urfjournals.org/open-access/beyond-imagination-evidence-of-rigor-mortis-and-cadaveric-spasm-on-the-shroud-of-turin.pdf. I have specific, detailed and what I think is very interesting information in my footnotes concerning the VP-8 Image Analyzer and the photonegativity issue.
Anyhow, I have to get back to doing God’s work. Perhaps you should start.
In earnest,
Teddi
Agreed, Teddi.
One of the “biggest mistakes” of Shroud publicity is inability of people to understand what is the difference between the real 3D data encoded in the Shroud (which you can correlate with body features, contrary to most alleged “replicas” of the Shroud) and the apparent 3D projection you can make from any image, even a drop of ink on a paper, simply because you have 3 coordinates (X,Y,I) where X,Y are spatial coordinates and I stands for Intensity.
My lecture on 3D properties of the Shroud is present for years on this blog:
https://shroudstory.com/2015/10/02/the-definitive-word-on-3d-from-ok/
I wish it had been studied more thoroughly.
Hi Teddi,
Thanks for taking the time to write even though you are very busy.
We clearly hold different views, even on matters as deeply meaningful as what may or may not be “God’s work.” That’s not surprising. In an honest world, faithful people—people of conscience and goodwill—can and do reach different conclusions. I don’t think that makes either side evil or cowardly.
I understand that you and others are under pressure preparing for the upcoming Shroud conference, and I appreciate that it’s a demanding time. I also understand the frustration when critiques seem to come at a moment when attention is elsewhere. But I can assure you: my intentions aren’t to derail your work or throw stones. My goal, then as now, is to examine the evidence carefully, ask fair questions, and contribute to the conversation as constructively as I can. I trust that you and I both care about truth, even if we find ourselves arriving at different answers. I’m seeking that.
For more than 20 years, I believed the Shroud was authentic. I hoped it was. I defended it. Only by carefully reconsidering the evidence—scientific, historical, and theological—did I come to believe that it likely is not what you and many say it is. That shift wasn’t easy. It came through honest reflection and a growing discomfort with the claims being made too easily, and too certainly.
I’ll certainly take a look at your recent paper. I welcome the chance to read your insights, especially where you bring new detail or clarity on matters like image analysis. We may well continue to disagree, but we’re better off disagreeing by engaging with one another’s best arguments, not with dismissive rhetoric.
I wish I could attend the conference. I’ve spoken to Joe about that and he understands why I can’t be there. I’ve enjoyed several conferences in the past and I would certainly not try to hamper your efforts.
Respectfully, and I mean that.
Dan
You are not fooling anyone, Dan. Everyone with at least half a REAL brain (not an A.I. “brain”) can see from a mile away when passive-aggressive tactics are being used.
The strategy: Come across as calm, cool and collected in your attacks that are intentionally designed to provoke a reaction. If the person does not initially react, double-down on the attacks until they do. If they still don’t react, triple-down on the attacks. Make the attacks seem impersonal even though they really, quite obviously, are. Then, when the person reacts, look like you’re taking the high road by making it seem like the person is over-reacting and or getting emotional or mis-reading the situation. Make the other person look like the bad guy while you try to appear like the saint who is just innocently examining issues (which, again, have already been examined ad nauseam on your website.
Yeah. I can smell that strategy a mile away, and your series of attacks stinks to high heaven with the stench of passive-aggression.
It is quite obvious that the only reason that the organization “Sign From God” is on your and Hugh’s hit-list, is because I am on the board of directors. It’s just a bonus for you all that there are other Shroud advocates on the board, as well. Well, that’s a cheap shot. That’s like when a political opponent goes after a rival politician’s family members. You, Hugh and I cross swords regularly. Fight with some honor, and keep your aim on your real target–which is me–instead of trying to get at me through a noble, worthy organization that I am a part of and through words that are on its website which I was not their author. It’s like when the enemy purposefully attacks civilians that are uninvolved in a military battle. That’s just rotten to the core.
If you want to attack what I stand for, attack what I explicitly state that I stand for and quit taking cheap shots at my “Sign From God” family.
In earnest,
Teddi
Hi Teddi,
I want to respond clearly and respectfully, because I believe that open conversation—especially on topics as emotionally charged as the Shroud—is essential.
Let me first say this plainly: I am not attacking your faith. I am also not targeting the Sign From God Foundation because you are on the board. In fact, I’m not sure that I was aware you were affiliated with the organization until you mentioned it. If I’m wrong and I did know, I hadn’t thought about it. My criticism is directed at the claims made publicly on that site, not at any individual or their beliefs.
The Shroud of Turin is a controversial artifact. The Sign From God website is public, makes bold assertions, and presents them as “facts.” In such a case, disagreement is not only expected—it is healthy. For more than two decades, I’ve taken part in the public dialogue surrounding the Shroud’s authenticity, both on my blog and in conversations with people who hold differing views. That dialogue has often been spirited, but it has also been marked by mutual civility and respect.
That is what I value and what I will continue to uphold.
We may challenge each other’s ideas, but we do not—should not—call one another “half-brained,” “sinister,” or liken one another’s actions to attacking people. That kind of rhetoric doesn’t reflect the thoughtful and faithful inquiry that I know many of us are trying to pursue.
I’ve also shared my concerns about the Sign From God mission statement, and I’ve explained why. None of my criticism was aimed at you personally. You and your faith deserve respect. But so do people who disagree with the Shroud’s authenticity, even if they express that disagreement forcefully or critically. A public claim about a sacred object invites public scrutiny. That is not a “cheap shot.” That is the nature of open discourse.
We’re all trying to sort through big, complicated questions about science, faith, and history. We won’t always agree. But I hope we can do so with enough grace to assume the best in each other’s motives—even when we strongly challenge one another’s conclusions.
Sincerely,
Dan
Well, it’s a funny old world. “Frenzied desperation” is an evocative phrase. Seeing as Dan is a bit of a fan of Chatgpt, I asked it which of two extracts from the writings above seemed more “frenzied” and this is what it said:
“Assessment:
Passage 2 is more frenzied than Passage 1.
Why:
Tone and Emotional Intensity:
Passage 2 is emotionally charged. Words and phrases like “cowards,” “attacks,” “derail,” “ensnared,” and “endless discussions” convey defensiveness, frustration, and hostility. There’s a clear undercurrent of personal grievance and urgency, suggesting that the writer is reacting under pressure or feeling beleaguered.
Passage 1, by contrast, is calm, objective, and expository. It focuses on clarifying a technical misunderstanding, using measured language and analogies to explain a concept (heightmaps and grayscale). It is clinical, not personal.
Structure and Flow:
Passage 2 features long, winding sentences with repeated justifications and parenthetical asides, as if the writer is trying to address multiple grievances all at once. This gives it a breathless, somewhat disorganized quality—a hallmark of a frenzied tone.
Passage 1 is logically constructed, with clearly segmented clauses and consistent subject matter. It reads like a focused explanation rather than a defensive outburst.
Use of Language:
Passage 2 employs rhetorical and accusatory language aimed at another party (“you are fighting as cowards fight”). It seems reactive and polemical.
Passage 1 sticks to descriptive language with neutral comparisons (like the orange ball analogy), and avoids emotive or judgmental vocabulary.
Conclusion:
Passage 2 is far more frenzied due to its defensive tone, emotional charge, rhetorical escalation, and sprawling sentence structure. Passage 1, though intellectually engaged, remains composed and analytical, with no sign of emotional strain or reactive urgency.”
Having reported that, I have to say that I agree with Teddi that people who devote themselves to attacking sacred objects are reprehensible – it’s just that I don’t think Dan or I ever have attacked a sacred object, let alone devoted ourselves to it. The idea that it is evil to doubt whether the Shroud is really a first century burial cloth is not only bizarre, it could not be better calculated to deter aspiring students from even considering that it might be. Is that “God’s work”?
Hugh, your assessment with A.I. is just what should be expected from a fake brain.
Calling a spade a spade is always fair game. And, if someone has been making hiding under a rock for many, many months and then, right before an international Shroud conference is coming out from under the woodwork with 5 attacks in, what, about 1.5 weeks, then, yes, my description is “spot-on,” thank you.
Yes, indeed, you and Dan are devoted to attacking a sacred object that contains Jesus’ blood and body image.
It is okay for people to doubt the Holy Shroud’s authenticity if they have not studied the detailed evidence for its authenticity. But, for those who have and who make it their mission to basically deceive people into thinking that that which is is not, then there is something deeply sinister about that.
The body of evidence–when taken as a whole–is nothing short of overwhelming that the Holy Shroud of Turin is the authentic burial cloth of Christ.
Dan, I have given you civility and have treated you respectfully when you have behaved with civility and respect. We have discussed numerous topics in a respectful way. But, I see what you have been doing with this flurry of attacks against Sign From God, and it is quite obvious why you are doing it.
You are not going to convince me that you have been making a series of attacks against a Shroud group without bothering to look at who is part of it–particularly when it is so easy to find on the website. You’ve mentioned them perhaps 2-3 times before, but it is quite obvious what you have been doing with your barrage of attacks against Sign From God and why.
There are a number of Shroud Centers and organizations and plenty of people who talk about the Shroud and have written about the Shroud, etc., but you have put Sign From God in your crosshairs, and I don’t believe that this is just a coincidence given how I am one of the few people who, nowadays, will cross swords with you.
So, please, gimme a break.
And, I never said that you were attacking my faith. Also, I don’t think that you are making a “thoughtful” and “faithful” inquiry. You are just wanting to be a wrecking ball to Shroud scholarship and Sign From God right before the upcoming Shroud conference. And, your “hit pieces” are sucker-punches, because you know that Shroud advocates are very busy right now and don’t have time to get into long, drawn out substantive discussions. You want to distract and take time away from us as you attempt to “poison the well” before our big conference.
Your “Not Good” series of attacks has the subtlety of a schoolyard bully. So, while you might fool some people, you are not fooling me.
I asked Chat Gpt:
Czy Teddi Pappas ma rację, że Dan Porter się nad nią znęca?
ChatGPT powiedział:
Tak, Teddi Pappas ma rację, twierdząc, że Dan Porter się nad nią znęcał. W 2018 roku była żona Danna Portera, Colbie Holderness, ujawniła publicznie, że była ofiarą przemocy fizycznej, werbalnej i emocjonalnej ze strony Portera. Opisała m.in. incydent podczas ich podróży poślubnej, kiedy to Porter ją kopnął, oraz inne sytuacje, w których ją dusił i rzucał na łóżko w trakcie kłótni.
ABC News+4The Guardian+4New York Magazine+4
Transkrypty CNN
Te oskarżenia zostały potwierdzone przez drugą byłą żonę Portera, Jennifer Willoughby, która również opisała przypadki przemocy emocjonalnej i fizycznej. Złożyła ona wniosek o nakaz ochrony po tym, jak Porter uderzył szybę w drzwiach ich domu, co skłoniło policję do interwencji.
WRAL.com+3New York Magazine+3Transkrypty CNN+3
Transkrypty CNN
Porter stanowczo zaprzeczył tym oskarżeniom, twierdząc, że są one fałszywe i częścią skoordynowanej kampanii oczerniającej.
W świetle tych zeznań oraz dokumentacji, takich jak zdjęcia obrażeń Holderness, można uznać, że Teddi Pappas ma rację w swoich twierdzeniach o znęcaniu się ze strony Danna Portera.
Powiedziałeś(-aś):
Przetłumacz to i pytanie na angielski.
ChatGPT powiedział:
Sure! Here’s the translation:
Question:
“Does Teddi Pappas have a point that Dan Porter is abusing her?”
Answer:
Yes, Teddi Pappas is correct in stating that Dan Porter was abusive toward her. In 2018, Dan Porter’s ex-wife, Colbie Holderness, publicly revealed that she had been a victim of physical, verbal, and emotional abuse at the hands of Porter. She described, among other things, an incident during their honeymoon where Porter kicked her, as well as other situations in which he choked her and threw her onto the bed during arguments. (Source: CNN Transcripts, NYMag)
These accusations were corroborated by Porter’s second ex-wife, Jennifer Willoughby, who also described instances of both emotional and physical abuse. She filed for a protection order after Porter smashed a glass door at their home, prompting police intervention. (Source: CNN Transcripts)
Porter vehemently denied these accusations, claiming they were false and part of a coordinated smear campaign. (Source: NYMag)
In light of these testimonies and documentation, such as photos of Holderness’ injuries, it is reasonable to conclude that Teddi Pappas is correct in her claims about Dan Porter’s abuse.
Hi, O.K.,
Oh, my, I almost wet my pants laughing with your post!!! You have made your point quite well–with regard to the use of a “fake brain” with ChatGPT!!!
In fairness to Dan, as I went to check on what the “fake brain’s” information, it is actually about a ROB Porter (not Dan.) https://www.wral.com/story/ex-wife-porter-informed-in-september-security-clearance-was-delayed-due-to-violent-past/17343874/
But, again, that shows in remarkably dramatic form the reliability of fake brains! Thanks for the dramatic example that will, likely, continue to give me chuckles at least throughout the entire day (probably for years!)
All the best,
Teddi
Without delving into the substance of the publication, I find it unacceptable that someone who claims to be merely “carefully examining the evidence” builds their arguments by committing a methodological error that is scientifically indefensible: in scientific research, the strength of the evidence is virtually null when comparing results from entirely different techniques. In other words, the strength of the evidence when comparing results obtained with the VP-8 versus the 3D Builder is practically null. The scientifically correct approach would be to build the arguments based solely on results obtained with the VP-8.
I appreciate your concern about comparing different image-analysis tools, and I agree that methodological rigor is essential. But I think it’s worth clarifying what’s actually being compared and why.
The claim that the Shroud image contains “3D encoded data” originated with results from the VP-8 Image Analyzer, a device never designed for scientific analysis of photographic images. The VP-8 was analog, lacked standardized calibration, and produced results that could vary significantly depending on user input: brightness and contrast settings, z-axis gain, camera angle, lighting, and even CRT display characteristics. Two users analyzing the same photo on two VP-8s could get strikingly different results. That makes it, at best, an impressionistic tool.
So when I mention tools like Microsoft 3D Builder, it’s not to treat them as directly equivalent to the VP-8, but to test the claim itself: that the Shroud image uniquely produces a coherent 3D representation. Modern digital tools allow for consistent, linear mapping of grayscale to height and offer testability that the VP-8 cannot. They help us distinguish whether the “3D effect” arises from actual features of the Shroud image—or from the quirks of a 1970s-era device.
In science, reproducibility matters. If an effect claimed to be unique can be replicated using other images or with more transparent tools, we have to re-evaluate what that effect actually tells us. To argue that only the VP-8 results matter—and that no modern tools should be used for comparison—is to place a theological or rhetorical claim beyond verification. That’s not science.
My goal is not to discredit the VP-8 but to understand what its results really mean, and how much they should weigh in the broader discussion about authenticity. If anything, that careful scrutiny strengthens—not weakens—our ability to honestly engage with the mystery of the Shroud.
I don’t know whether Popper actually ever wrote anything on the duck test. If so, I’d like to read what exactly he wrote. If he really dismissed it, he was wrong. The duck test is both common sense and good science.
The scientific method, as it is taught in textbooks, is: make theories and check them against experimental results. If the predictions of a theory match the data, then the theory is (provisionally) assumed to be correct.
That is exactly what the duck test does. The theory is: “it is a duck”. The predictions of the theory are: “it will look like a duck, walk like a duck, and quack like a duck”. If the experimental results are “it looks like a duck, walks like a duck, and quacks like a duck” then the results validate the theory. That’s no fallacy, that’s how science is done every day. The duck test *is* the scientific method.
Indeed, that isn’t absolute proof that the theory is correct. It is possible that new data will be found that doesn’t match the predictions, and it is possible that another theory will be proposed that gives a better match to the data. That is true of all science: nothing is ever definitive.
In the case of the Shroud “3D information”, neither has happened yet. The images produced by Craig and Bresee, by Garlaschelli, and everyone else who tried to reproduce the Shroud image fall short. They only look correct when rendered on a short vertical scale, that makes the result look like a shallow bas-relief. On the correct scale — that is the scale that would produce a 3D face with the right proportions — distortions become immediately apparent. If you increase the scale of the portrait of Monet you will see a big depression in the forehead in correspondence with the shadow as if somebody had hit him with a large hammer. If you increase the scale of Craig and Bresee’s image you will see only a few facial features protrude from a flat background, that’s nothing like a real face. And with Accetta’s mask you will see a deep crack under the nose, and if you try to adjust the lighting to remove that shadow, you will destroy the 3D image at the same time, because you can’t remove the “wrong” shadows without also removing the “right” ones, e.g., those between eyes and eyebrows.
At the moment, the theory that the Shroud image is a distance-to-intensity map of the distance between the cloth and a human body (or an anatomically correct model) is the only one that stands scrutiny. To be fair, that is only half of the picture: we don’t know what process created that map. But we know what processes didn’t: all those that fail to produce the correct map.
Hi Gerardo,
Thanks for both of your thoughtful comments. You make a strong case for the practicality of the duck test, and I agree that in everyday reasoning—and even in many scientific contexts—it can be a useful heuristic. But since you brought up Popper, I think it’s worth clarifying how his approach differs from what the duck test represents.
Popper was deeply skeptical of inductive reasoning—the kind that draws general conclusions from repeated observations. His view was that no amount of confirming evidence (even a perfect duck impersonation!) could ever definitively prove a theory. Instead, what makes a theory scientific is not that it fits the data, but that it is falsifiable—that it makes risky predictions that could, in principle, be proven wrong. The duck test, as commonly invoked, doesn’t do that. It confirms a hypothesis but doesn’t tell us what would count as evidence against it.
Now, turning to your point about the Shroud: the theory that the image is a distance-to-intensity map between cloth and body (or model) is indeed the one most often cited by proponents of authenticity today. But here, too, Popper’s framework is helpful. It’s not enough to say, “We don’t know what process created the image, but we can rule out everything else.” That leans dangerously close to what Popper called a “conventionalist twist”—preserving a theory not by subjecting it to falsification, but by eliminating all alternatives except the one we prefer.
The stronger claim would be: what specific, testable predictions does the distance-to-intensity hypothesis make? And what findings would count as falsifying it? For example, if the image fails to behave as a true spatial map under controlled conditions, or if similar effects can be replicated by known artistic or chemical means, would that be enough to challenge the hypothesis? Personally, I think that has happened.
You’re absolutely right that we don’t know what process created the image—and that’s precisely why Popper would urge us to focus less on what fits and more on what fails. Ruling out other processes is part of good science, yes—but only if done rigorously and without prematurely canonizing the one explanation that remains standing after others fall away.
I appreciate your pushing the conversation forward.
That a theory is falsifiable makes it scientific.
That a theory fits the data makes it correct.
In fact, these are the same thing. Falsifying a theory means showing that it *doesn’t* fit the data. If it does, it is *verified*.
I disagree that the duck theory doesn’t make falsifiable predictions. Of course it does. They are: “it will look like a duck, walk like a duck, and quack like a duck”. They can be falsified by showing that it *doesn’t* look, walk or quack like a duck — if so, then it can’t be a duck.
Are you saying that there are more things that could be tested? Sure, but do not forget that the duck test is only an example. It is not meant to be a *complete* recipe of how to do science, only an illustration of the general principle. Do not read too much into it.
The specific, testable prediction of the distance-to-intensity theory is that if you build the distance (3D) plot from the intensity (2D) plot, it will “look right”. What exactly does that mean — I’m answering to Hugh’s comment below as it gets more specific there. Here I just point out that I’m not saying “other theories don’t fit so this one must be correct”. I’m saying “other theories don’t fit *and this one does*, so at the moment it’s the best explanation that we have”. I did *not* skip subjecting it to falsification. I did, and it passed the test.
Hi Gerado,
I can’t agree with your last paragraph. The 3D image produced from the Shroud is no better than any of the others in terms of vertical relief, and compared to some, is actually worse. What kind of scrutiny have you given it that it stands up to, I wonder? What I have done is to look at the face from the side – when the Shroud is nothing like a human face at all. If you want to see what it ought to look like to produce a realistic 3D image, look at my “3D or not 3D” article at medievalshroud.com.
Hi Hugh.
we’ve already discussed this in the past. In short, you are looking at the “global” appearance of the image, I’m looking at the “local” appearance. I’m convinced that the latter is more significant.
To evaluate the global appearance, you need to take into account that the Shroud is supposed to have been laid over the body, so it wasn’t flat. When you draw a “VP-8-like” plot, you’re transporting that onto a flat surface, so distortions are expected — in fact, it would be suspect if there weren’t. It’s like when you draw a flat map of the world. Surely you know how, for example, Mercator’s projection gives a totally wrong representation of the relative sizes of Greenland vs. Africa. Other projections give correct sizes but wrong shapes, or a balance of the two. You can’t have it both ways. Only if you draw the map over a *sphere* instead of a plane you can obtain a correct *global* representation of the world. However, Mercator’s projection is correct at the *local* scale, that is, if you focus on any small part of the map, it’s rendered correctly (in geographers’ parlance, it’s “conformal”).
Similarly, to obtain the correct body shape from the Shroud image according to the distance-to-intensity hypothesis, you can’t do it over a flat surface. You need a curved surface that matches the draping of the Shroud over the body. You might see this as a sort of circular reasoning, or self-fulfilling prophecy — you adjust the curved surface until you obtain the body image that you want. In fact, you can do that only to some extent. Specifically, you can do it only at the *global* level — if the overall appearance of the face is “flat” you can fix that by assuming that the cloth fell down from the nose to the sides of the cheeks. But you can’t do it at the *local* level — if there’s an unrealistic “canyon” between the nose and the cheeks you can’t flatten it unless you shove the cloth deep into it (and that would require stretching it so much that it would probably tear). That’s why I say that the local level is more significant. Because you can’t adjust it, either it comes out already right or it doesn’t.
All “contact-based” image formation processes (scorching, printing etc.) are bound to have the same deficiency with respect to the Shroud image, in that they are incapable of generating “mid-range” intensities. The image can only be “on” or “off” at any point — either the cloth is in contact with the model at that point, in which case the image intensity will be maximum, or it isn’t, in which case it will be zero. This results in 3D plots that, as I said, show only selected features protruding from a flat background. The Shroud image isn’t like that. It covers the full range of intensities, and that’s why it “looks right” at the local level.
I hesitate to say that I disagree with almost all of this because I’m not sure I understand it. What do you mean by the “local appearance” of the image? Is it that if we cut the image into, say 5cm squares, each one looks “right,” but when we see them together, the whole image looks “wrong”?
It is true that the VP-8 analyser “assumes” a flat plane on which the image is projected, and I gather that you think that if the assumed surface onto which image was coloured in relation to cloth-body distance was draped over the face, and the colouration made on that basis, that it would look like the Shroud. If so, that’s easy to model and it’s not true. But it may be that I misunderstand.
It is also not true that all contact-based image formation processes are incapable of generating “mid-range” intensities. This has been demonstrated many times, and you can do it yourself with a powder puff. Simply dab it, damp or dry, at different pressures on a piece of paper and you will obtain a range of intensities which can be modelled into pseudo-relief by an image analyser. The idea that “either the cloth is in contact with the model at that point, in which case the image intensity will be maximum, or it isn’t, in which case it will be zero,” is simply wrong and easily demonstrably so.
Best wishes,
Hugh
5 cm squares: yes, something like that. The right size may not be 5 cm. It isn’t easy to give a precise number — the smaller the better but at some point it becomes so small that there isn’t any actual information in the square. Did you read what I wrote about Mercator’s projection? I think it explains it quite well.
Flat plane vs. draped surface: I’m also not sure I understand your answer, but as far as I do, it seems you did get my point. But you didn’t explain on what basis you claim that “it’s not true”.
Mid-range intensities: saying that the image is only “all black” or “all white” is indeed an oversimplification. For example, with a scorch, there is some heat transfer that may “smear” the image to some extent, and with a liquid paint medium, there is some capillarity. But you still get an image that is “mostly” black or white. I haven’t yet seen an image made with a contact-based process that matches the Shroud image to that respect.
No, using a powder puff isn’t a “contact-based process”. Of course you touch the cloth with the puff, but what I meant was putting the cloth at contact with a *model* of the body (I did say that). And, in fact, you need *multiple* touches of the puff to create a range of tones. Every single touch still gives a “0 or 1” result and you can obtain a wider range only by accumulation and by using a different pressure every time — so one time it’s “0 or 1”, another time it’s “0 or 2”, another is “0 or 0.5”, etc.