Variegated pattern evidence of pre-medieval bleaching
Variegated pattern also known as plaid pattern and banding. Not related to the weave of the cloth.
Variegated patterns of whiteness 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. This was common prior to the medieval era but not the common method of bleaching linen in medieval Europe where the cloth was sun bleached in bleaching fields."
The residue coating of starch fractions and saccharides on the outermost fibers is consistent with an evaporation concentration. This is the sort of residue that forms when trace amounts of starch and sugar substances in rinse water are moved to the surface as water wicks to the outside of a cloth as it dries. The saccharides in the coating are like those found in Soapwort (saponaria officinalis). These include glucose, fucose, galactose, arabinose, xylose, rhamnose, and glucuronic acid). This coating is about 1 percent to 4 percent of the thickness of the fibers. Where there is image color, the color is completely within, and the result of a caramel-like chemical change to, the otherwise clear evaporation concentration layer.
The residue coating is expected from first century methods of linen manufacturing described by the historian Pliny the Elder. Because the warp threads on the loom were coated with starch as a lubricant, the cloth was then rinsed with soapwort to remove the starch and laid out to dry. The bleaching of hanks of yarn before weaving, which is also consistent with first century methods, causes the variegated patterns. Hank bleaching is not consistent with medieval European field bleaching of finished cloth.
