(12-18-2023, 12:57 AM)Ninurta Wrote: I too have followed the investigation into the Shroud of Turin since the  days of the VP8 Image analyzer and the STURP Investigation, There is  some information not presented in the videos, or which is inadequately covered, that I'd like to bring forth.

The image is faint. Very faint. The images we usually see are  contrast-enhanced to bring out the detail of the image, to a more  visibly obvious level. The image is so faint that the cloth must be viewed from a distance for the image to be seen at all. When you get too close to it, the faint differences in the fiber colors just merges together into one color or shade of color.

The image is in the "negative", probably due to the method of  production. It was not seen as a positive until the photographs of  Secundo Pio in the early 1900's. A positive image was seen to occur on  the negative plates of his photography sesstion.

The image is ONLY on the surface. The VERY surface. it only goes one  fiber deep into the cloth. Not one thread deep, but on FIBER deep on the very surface threads of the weave.

The image was produced by a process of "dehydrative oxidation" - a fancy way of saying burned or scorched. There is no pigment in the image as  would be present in a painting. The color of the very surface fibers was
changed (against the background color) by a process of scorching. This  could be produced by an acid burn, or by radiant heat or sufficiently  strong radiant light.

The 3D effect is a result of varying distances of the cloth from the  radiant energy source. Radiant energy attenuates as the inverse of the  square of the distance from the source (1/d^2). At twice the distance, it is 1/4 as intense. at 3 times the distance, it is 1/9 as intense.. at 4 times, 1/16th, and so on. So, more distant areas would be less  affected by the radiant energy. That's why I think it's more likely to  be caused by some sort of radiant energy than say for instance an acid  burn. Acid would have been applied more uniformly, and would not have  produced the proper 3D effect.

It's pretty similar in end result to some 3D imaging techniques I've  tinkered with over the years. Specifically grayscale bitmaps (or "heightfields"). In  grayscale bitmaps, each pixel is represented by a different grayscale  level, and each grayscale level represents a different elevation or  distance. I've used it to reproduce 3D terrain elevations on maps from  grayscale 2D images.

Years ago, there was software available called "basrelief.exe" that  claimed to create 3D images from 2D originals, but it had flaws. The 2D  image used to create the 3D image had to be directly photographed, and
the flash used. The reason was that the software pulled it's depth  information from the intensity of the flash that struck the photographed surface - brighter intensity was interpreted as closer to the camera.  Any other lighting, such as ambient light striking the surface from  another angle, would distort the 3D result image. About the only way to  make it work approximately correctly was to photograph the subject in  complete darkness so that only the flash from the camera provided any  light for the software to interpret

Grayscale bitmaps are pure height level information presented as an image. White is "higher" or "closer" and black is "lower" or "farther". shades of gray represent varying distances in between - lighter gray closer, darker gray farther. So height levels can be reconstructed and then artificially lit from the side or another angle to bring out the 3D quality of the image. Each pixel has it's own height based upon the intensity of the gray present in it.

I doubt that anyone would have had that experience or information concerning heightfields or grayscale bitmaps in medieval times, and the shroud is at least that old, so how was it produced?

If the shroud were wrapped around an actual body or a statue, the image would have come out distorted as it followed the curves of a body - but it didn't. It came out as if the cloth were held in a flat plane above and below the body (like a film negative in relation to the camera lens), and then "flashed" or "exposed" for lack of a better term.

How on Earth could that happen naturally, or in a process of fakery when such concepts were entirely unknown?

.

(12-19-2023, 06:32 AM)Michigan Swamp Buck Wrote: For as long as I have gone to college and studied and worked with digital graphics in the past 30 plus years I have never heard about what you describe here. I even worked with stereo images I produced and developed in my own darkroom as well as built my own stereoscope to view them with. When I got into digital images I made a pair of red-blue filter glasses to view my 3-D images with, that trick helped me land a good graphics job too.

But what you have described makes absolutely perfect sense when I think about the grayscale images I've made and worked with over the years. What a great concept, it should have been covered in my fine arts college classes (too long ago I guess) I bet it was used on NASA projects all the time. Kudos for that information.