A 2.1. Holes
A 2.2. Hair remains
A 2.3. Striations
A 2.4. Traces of jagged action
A 2.5. Veining, vein evidence, drainage of blood vessels
A 2.6. Variation in thickness
A 2.7. Opacity, transparency
A 2.8. Splitting
A 2.9. Variation in colour or surface appearance, matte, semi-matte, glossy
A 2.10. Presence of grain layer
The signs of the skin’s quality that mostly depend on the age of the animal.
It is easier to produce thin, ca 0.1 mm and thinner, parchment of uniform thickness if the skin of a young animal is selected for processing. The processing of both sides of an older animal’s skin in order to thin it requires much more effort, and is often unsuccessful. The damage and uneven thickness of the base material of historical parchments is usually caused by the mechanical processing and stretching during thinning of the skin. Parchment with variations in its thickness may later become quite stiff. Great differences in the thickness may result in the deformation of the parchment caused by the external environment.