coating.jpg
Figure: Three different views of an image-fiber coming from STRUP-1EB; there is visible a zone on the left of the linen fiber where the external colored layer was lost due to a mechanical stress; in this zone it visible the non-colored medulla (photo G. Fanti).


CHEMICAL-PHYSICAL CHARACTERISTIC OF THE LINEN YARNS AND FIBERS

The image is a result of concentrations of yellow to light brown fibers (A11), the image-formation mechanism did not char the blood (A12), hold at a relatively low temperature (A13) and was not painted with any of the expected, historically-documented pigments (B9) also because there are no pigments on the body image in a sufficient quantity to explain the presence of an image (B13).
There is no protein painting medium or protein-containing coating in image areas (B10). The image fibers do not show any sign of capillary flow of a colored or reactive liquid (B11).
The image color resides only on the topmost fibers at the highest parts of the weave (A2); it resides on the thin impurity layer of outer surfaces of the fibers (A4).
The color of the image-areas has a discontinuous distribution along the yarn of the cloth: striations are evident and color concentration can be detected in correspondence to crevices where two or three yarns cross each other (A5).
The colored coating cannot be dissolved, bleached, or changed by standard chemical agents, but it can be decolorized by reduction with diimide (A9).
Polysaccharides of lower stability than cellulose are present on the surface of linen fibers (A10).
There is no cementation signs among the image fibers (A17) and no fluorescent pyrolysis products (A19).
The chemical properties of the coatings are the same as the image color on image fibers (B12).
The cellulose of the medullas of the fibers in image areas is colorless (A6) and its crystal structure has not visibly changed (A8).
There is no observed microscopic, chemical, or spectroscopic evidence for the presence of any dry powder responsible for the body image on the TS (A82). Aldehyde and carboxylic acid functional groups were detected in the TS fibers (A87).