Animal skins have been written and drawn on since the Ancient World, and methods to prepare them refined. Parchment and its highest quality form, vellum, are the culmination of that development. Skins are soaked in an alkaline solution for over a week and scraped clean of hair, fat and viscera: essentially leaving a mesh of pure collagen fibres. This is stretched out and left to dry under tension, then scraped again to an even and desired thickness.
Parchment has seen various uses throughout the world, as drum-skins, shields, window panes and for interior decoration, for example as lamp-shades and wall panels, favoured for its durability and soft, subtle tones. However, it is in manuscript culture that parchment and vellum endures most significantly. Beginning in the form of scrolls, the use of parchment evolved hand-in-hand with the creation of book structures and their development. As well as being the written page, parchment saw use as the material for sewing, sewing support and covering.
From the 15th Century, printing decreased book production costs and rapidly spread the use of paper as the written page. However, parchment and vellum still held authority as the writing material of longevity and refinement; legal documents, government records and diplomas continue to use the material. For high end calligraphy, vellum is refined further by polishing the surface perfectly smooth.
The library holds examples of parchment and vellum manuscript pages that were recycled to cover later books, including Indulgences printed by Gutenberg that were once used as pastedowns.
The drawback to parchment is its sensitivity to humidity. The addition of moisture undermines its tensioned structure, by loosening and untwisting the collagen fibres until they turn into gelatine. This process of gelatinisation cumulatively and irrevocably weakens the parchment.
Further detail on the process of parchment production can be found in this blog post.