A 2.10. Presence of a grain layer

Total or partial existence of the grain layer.

In the case of parchment made into a single-sheet document, the recto and verso sides were often treated differently and therefore were visually distinct. A grain layer on the verso side of the document has been occurring more frequently since the 15th century. For a variety of reasons, the existence of this layer can significantly accelerate the degradation of the parchment.