One Christmas, when I was very young, my father gave me a chemistry set. I remember the metal box filled with little bottles of chemicals, test tubes, stirring rods and a clamp for holding test tubes over a small alcohol burner.
That Christmas morning my father and I set up the chemistry set on the kitchen counter and tried some of the experiments described in a book that came with the set. I remember one of the experiments in particular because, now looking back on it, I think it had a profound impact on my life. It was probably the beginning of skeptical tendency that has affected my thinking throughout my life.
My father and I filled a small wine glass with water and added several drop of a clear liquid chemical called phenolphthalein. It looked like an ordinary glass of water. In another glass we added a few drops of ammonia. Unless you looked closely, or took a whiff, it seemed like an empty glass. We called my mother into the kitchen to observe and my father explained that I was going to perform a miracle and change water into wine. I then poured the glass of water into the empty glass and the liquid abruptly turned dark red. It looked like wine.
It wasn’t a miracle, of course. It wasn’t wine that I made. And there was a perfectly good chemical explanation for the deep red colored liquid. One of the first thoughts I had was that perhaps Jesus also performed some trickery at the wedding at Canaan. All the miracles, I thought, must have some logical explanation. And over time, as my understanding of science and history evolved, I became something of a modern iconoclast and a skeptic.
Now, some fifty years later, I discovered another “try this at home miracle.” The difference is that no one can provide an explanation for the results of this little experiment. I have been looking for a scientific explanation for the last five years and have yet to find anyone who can provide an explanation for the results. Most scholars who have studied the Shroud extensively agree that there is no explanation.
I invite you to try it. All you need is a home computer running Windows, a connection to the Internet, some software that you can download for free and ten minutes of your time. Detailed instructions follow the explanation below.
It turns out that only one known image of a human face can be rendered as 3D picture by plotting the darker and lighter shades of color in the image. The image is the face on the Shroud of Turin. No other image of a human face, whether from a painting, drawing or photograph will do this. Why is this so? Try the experiment or just read what follows. Try to explain it.
Some Basics
No one really knows how these images were formed. They were not painted as some, in the past, have supposed. The chemistry and physics of the image chromophore (that which gives visible image) are now well understood even though the method by which the images were created remains a mystery. The images are the result of a selective, color producing chemical change to discreet lengths of some cellulous fibers of the linen. Chemists describe the chemical change as an oxidation, dehydration and conjugation of the polysaccharide (long-chain sugar molecular) structure of the fibrils. Direct microscopic examination reveals that the image producing chemical change to the linen is superficial to the top one or two fibrils of the topmost threads of the cloth. There is no evidence of any matting, capillarity, wicking, or penetration expected from liquids. The images could not have been created with paint, dye, stain or liquid chemical. Numerous tests including visible, ultraviolet and infrared light spectrometry; x-ray fluorescence spectrometry; and direct microscopic viewing of the Shroud confirm that the images were not painted. Other tests on particle samples collected from the Shroud’s surface including microchemistry analysis, pyrolysis-mass-spectrometry, and laser-microprobe Raman analyses further confirm this.
The images, closely examined with the aid of microscopes and microphotography, are similar to halftone images. Simply, this means that all the different shades of color are derived from the number and size of pixels of a single color in any given area of the image. A pixel (picture element) can be a dot, a short line or, as with the Shroud, a discrete length of fiber colored by the chemical alteration of the cellulose. Halftone is the method used to print black and white photographs in magazines and newspapers. Look closely at a picture in a newspaper and you will see that all the shades of gray are achieved with dots of only black ink. Halftone is also the way black and white pictures are printed on inkjet printers connected to home computers. With such printers, every shade of gray is produced by minuscule droplets of black ink. Where there are more droplets of ink the printed image is darker; where there are fewer droplets the image is lighter.
The images on the Shroud are not black and white, but they are monochromatic; that is, they are of a single color. The color is often described as sepia or straw yellow. The color produced by the chemical change to the fibers is constant and the various darker and lighter tones of color we perceive are the result of the density of the altered fibers (length and quantity in a given area). It is interesting to note that on a high quality inkjet printer (1200 dots per inch), the ink droplets are about 60 microns across, whereas on the Shroud, the image-bearing fibrils are only about 15 microns thick or about one fifth the thickness of typical human hair.
Another interesting attribute of the images is that they are negative images; that is with dark and lighter tones of color reversed. In this sense, the images on the Shroud are like photographic negatives. In the example shown here, the image of a face on the left is as the image appears on the Shroud. The positive image on the right is as the image appears when the tones are reversed. This attribute was discovered more than a century ago, when in 1898, a photographer named Secondo Pia took the first-ever photographs of the Shroud with a large box camera. While developing his photographs he discovered that images that appeared on the glass plate negatives were positive images that were startling in clarity and realistic appearance. For the first time people could see the amazing detail in the Shroud’s images. It is not that the detail is not there on the Shroud. It is. But our minds are not well adapted to interpreting negative images. What for centuries had appeared only as ghostlike images now appear to be graphically remarkable front and back pictures of the man on the Shroud – and the face.
But they may not be pictures at all but something else. At least they are not pictures of a human face or body in a traditional sense. When we look at a picture of a person we are looking at a representation of what we see with our eyes. What we see with our eyes is the light reflected from the face or the body. We may see shape but that is only a consequence of seeing reflected light. Light, in all its colors and varying intensities, is all that our eyes can detect. While simple drawings and cartoons may only show outlines and features, leaving it to us to imagine depth, any picture that tries to convey a sense of dimensionality always shows how light is reflected from objects, faces, and bodies. This is true whether the picture is a sketch, painting, mosaic, photograph or any other form of two-dimensional art. On the Shroud, the face – in fact both body images – look like pictures of reflected light. We think they are pictures, but image analysts tell us they are not that at all.
Artists use many techniques to convey the sense of three-dimensionality in a painting or other flat-surface work of art: faces turned at angles, parts of an object or body protruding outward, placement of objects in front of other objects, perspective in which objects appear to become smaller as they recede into the distance, and the play of light on shapes and surfaces. We can see all of this in Carvaggio’s famous Supper at Emmaus shown here. Notice in particular the treatment of light on the subjects’ faces.
Of all of the methods used by artists to convey three-dimensionality, the play of light –highlights, lowlights and cast-shadows – is the most important method for showing depth in a human face. We seem to see this in the face of the man of the Shroud. But on close examination we see that what appears to be the play of light is not light at all.
Light, in order to produce highlights, lowlights and cast-shadows, must have direction. While light may come from many directions, bouncing off of walls and objects and diffusing in the air as it does, it must nonetheless have a primary direction. If it does not, there is no way to convey a sense of depth. Look at a picture of a ball or a globe. Without the play of light on its surface, without highlights and lowlights it will look like a flat round surface. By having directionality, light enables us to see that the ball is spherical. We can say that light is what the artist encodes on his canvas. Light, incidentally, is also what the photographer’s camera encodes on film.
When we look at the face of the man of the Shroud, we certainly seem to see depth from the play of light. Look at the tip of the nose, at the sides of the cheeks and the recesses of the eyes. But where is the light coming from? What is its direction? Image analysts, using computerized tools, tell us there is no light directionality at all. It doesn’t come from the left or the right, from above or below, or from the front. That is because the images we see on the Shroud are not representations of reflected light. The areas of darker and lighter tones are not encoded light. The body images and face we see so clearly are not pictures by the hand and eyes of an artist. Nor are they some form of medieval proto-photography as some have suggested in a vague attempt to explain the images’ photographic-like negativity.
It turns out that the Shroud images are terrain maps – and we can prove this. What is encoded onto the Shroud is a terrain map of a man’s head and body. Both the front side and the backside images are this. With space-age image analysis equipment or off-the-shelf graphics software running on a home computer we can plot this encoded information and produce a realistic isometric plot (an angular view of a three-dimensional shape).
The hazy donut shape shown here is an example of a terrain map for the crater rendered as a three-dimensional shape. Computer software, by plotting the different shades of gray as altitude, is able to produce the picture of the crater which is a simulated picture of reflected light.
It is important to stress that no identified works of art, no known artifacts or relics of any kind will produce a 3D plot like the one produced by the Shroud. Researchers have tried every imaginable artistic method including bas-relief rubbings, scorching with hot statues, daubing the surface with pigment dust, and image transfer rubbings. Nothing does or can be expected to produce a 3D plot. No one knows how an artist or crafter of false relics could have produced such an image. And certainly, no one knows why.
In the case of the Shroud we do not get a perfect three-dimensional rendering for many reasons: If, as scientists suspect, what is encoded on the Shroud, as data, is the distance between any point on the man’s body and the cloth loosely draped about him, then the distance will be distorted by the drape of the cloth. We can assume the cloth was not perfectly flat. Physicists have estimated that the maximum distance represented is about 3 or 4 centimeters, but we don’t know how linear the scale might be in the image formation process. We might know that if we knew how the images were created, but we don’t. The image is very old, medieval as some believe or possibly even older then that. We don’t know how fading or maturing of the images and the aging of the cloth might have altered the accuracy of the distance that is encoded. Finally there are bloodstains and dirt that cause distortions.
Some researchers have suggested that the images might have been formed by some perfectly natural process such as a chemical reaction between funerary spices and bodily fluids. Even chemicals used on the linen cloth for softening, whitening, or preserving might have induced images. The working premise for a naturalistic explanation has generally been that the Shroud may be the authentic burial cloth of the historical Jesus or someone else crucified in a like manner but that the images are not necessarily supernatural in nature; that is they are not divinely wrought or the accidental byproduct of a miracle.
Nothing has been found that works. So far, no method has been found that will produce the chemical change to the cloth’s fibrils, produce the negative image, and produce a spatially encoded 3D terrain map.
Are we to imagine that a medieval or pre-medieval craftsman knew of some method for producing the images, unknown or unrecognized by modern science? Whatever it was it seems to be without precedent in the arts, among other known relics, and among other artifacts of history. Whatever process a craftsman might have used, it seems never to have been exploited since.
3D Renderings
These image were produced electronically from the facial image on the Shroud. The green image was produced on the VP8 Image Analyzer at the Sandia Labs in New Mexico. The white images were prepared with Corel's Bryce 5 for Windows. They are dramatic in the amount of 3D rendering.
Doing the Experiment
Using POV-Ray 3.5
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Download POV-Ray 3.5 (or later) from http://www.povray.org/download/. The software is free. There are versions for Windows, MAC OS, MAC OSX, and Linux. The instructions that follow are for Windows but should be easily followed by others.
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Open the download file to install the program. I recommend that you follow the default locations for the program by installing it within Program Files. Povwin35.exe
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Using “My Computer” locate file folder “POV-Ray for Windows,” within it the folder “Scenes” and within that the folder called “Objects.”
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Download the following two files into the “Objects” folder:
source picture for rendering (shrdface.bmp)
pov file (shroud.pov)
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In POV-Ray, open the file called “shroud.pov.” Then click on “Run.”
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Experiment with different camera and lighting angles by changing values in shroud.pov.
Note that the image of the face used with POV-Ray has been smoothed and reduced in contrast to accommodate limitations in POV-Ray. The image must be smoothed (blurred) to avoid dramatic peaks and valleys in the rendered picture. Jasc Paint Shop pro was used for smoothing and contrast reduction.
Using Jasc Paint Shop Pro 7.0
If you have a copy of Jasc Paint Shop Pro you can easily conduct the experiment by simply opening any picture of the Shroud of Turin and clicking on Effect, Artistic Effects and Topography. Initially, set the width (smoothing) to 12, the Density to 100 and the Lighting Angle to 45 degrees. The experiment with different values.
This article was adapted from "An Open Letter to John Dominic Crossan: Dear John, What Were You Thinking" Anyone wanting more details about the Shroud of Turin should read the entire letter.
