The honest skeptical inquirer considers . . .
What is the nature of the Shroud of Turin cloth?
The cloth is linen. It is a single piece, measuring about 14 feet by 3½ feet. The weave is a 3 over 1 herringbone weave. It was made on a hand loom. It is approximately 350 micrometers thick though in some places it id as thick as 390 micrometers and as thin as 315 micrometers. For comparison, a sheet of typical 20lb paper used in copiers and inkjet printers is 100 micrometers thick, about the same thickness as human hair.
The yarn (thread) consists of approximately 70 to 120 flax fibers twisted together in a Z-twist (clockwise). The various lengths (hanks) of yarn are not spliced together but layed side-by-side during the weaving. Variegated patterns of colors in both the warp and weft yarn indicate that the yarn was bleached before weaving rather than after the cloth was taken from the loom.
The thickness of the fibers from flax plants varies significantly as they do in the yarn of the Shroud. The average thickness of Shroud fibers is about 13 micrometers or 13,000 nanometers (a typical human hair is about 100,000 nanometers thick).
There is an evaporation concentration layer of starch fractions on the outermost fibers of the yarn. This coating, in very approximate terms, is about 1 percent to 4 percent of the thickness of the fibers. In other words, the evaporation concentration is, at its thickest, about 1/100 the diameter of human hair.
Where there is image color, the color is completely contained within the evaporation concentration layer suggesting a caramelization or Maillard reaction.
See: What is a Maillard reaction (Chemistry)?
