16. What are the optical and physical properties of flax fibers (linen)?
- What Shroud image properties have been observed objectively by scientific methods?
- Can the presence of a "bioplastic polymer" coating anywhere on the Turin Shroud be confirmed? Could it affect the radiocarbon age determination?
- Could a "bioplastic polymer" affect the radiocarbon age of the Shroud of Turin?
- How do you know that the image on the Shroud of Turin was not painted?
- How do you know that there is real blood on the Shroud?
- How do you know that the image was not produced by radiation?
- How do you know that the image was not a scorch? How do you know that most of the Shroud had not been heated enough to start decomposition?
- How do you know that the radiocarbon sample was not valid for dating the Shroud of Turin?
- How do you know that the fire of AD 1532 did not start a long-term autocatalytic decomposition of the Turin Shroud?
- Why are there bands of different colored linen throughout the Shroud, and what do they prove about image formation mechanisms?
- How fast does cellulose (linen) decompose (produce a color) compared with the impurities found on the Shroud of Turin?
- How is it possible to get image only on the topmost surface of the cloth of the Turin Shroud?
- Can some simple, natural process explain a doubly-superficial image?
- How fast does a human body begin to decompose, and what are the products?
- How do you know that the flax fibers were not involved in image formation?
- Are there any other ways than radiocarbon to date the Shroud of Turin?
- What could be observed about image properties by looking at the damage from the fire of 1532?
- What options for future scientific study of the Shroud's history and image were lost as a result of the "restoration" of 2002?
Answer to # 16:
Flax fibers look like small lengths of bamboo under a microscope.
The gross internal composition of a flax fiber is shown in the figure (after Cardamone).
The cellulose molecules in flax fibers are folded back and forth in a fairly regular arrangement, and they show the properties of crystallinity. The fibers are composed of closely packed "ultimate cells" of the fibrillar structure that are cemented together with holocellulose and lignin. You can see the ultimate cells under a microscope, and abraded fibers often show ultimate cells sticking away from the surface. These were the structures that were mistaken for "filamentous bacteria" by Garza-Valdes.
When you rotate the stage of a petrographic microscope with crossed polarizers while looking at a flax fiber, straight lengths change from black to colored every 45?. The fiber is birefringent and has an ordered structure. Most of the cellulose of the fibers is in a crystalline structure. In structures like flax, it is called a "fibrillar" structure.
McCrone ignored our agreements for work on the STURP sampling tapes: he stuck them all down to microscope slides. This made observations much harder; however, flax and cotton fibers can still be distinguished by their indexes of refraction.
Crystallographic observations must be made on the specific fibers that reach extinction at the same angle as the tape (while everything is black). The index of refraction of a normal linen fiber parallel to its length is nearly identical to that of the adhesive on the sampling tapes (it nearly disappears). That index is very close to 1.515. The index across the fiber is appreciably lower than the adhesive. The indexes of refraction and crystallinity of image fibers are identical to unaffected fibers. Bent, crushed, or otherwise damaged fibers show strain dichroism and will give an erroneous index. Most flax fibers show intense birefringence colors when they are viewed at a 45º angle from the plane of polarization of the microscope.
Cotton has a low birefringence, usually appearing white (first-order white), and it is a thin, wide tape that shows periodic reversals (twists).
© 2004 Daniel R. Porter, Bronxville, New York
