380. Three Types of Parchment

Tefillin, Mezuzah v’Sefer Torah 1:6

There are three kinds of parchment: g’vil, klaf and duchsustos. First, the hair is removed from the hide of a domesticated or wild animal. It is salted and prepared with flour. Then resin and other substances are applied so that the hide will contract and harden. This kind of parchment is called g’vil.

Tefillin, Mezuzah v’Sefer Torah 1:7

After removing the hair, the hide may be divided into two parts in way that parchment-makers know how to do. There are then two pieces of parchment: a thinner one on the side where the hair grew, and a thicker one, on the side where the flesh was. After preparing it with salt, flour, resin, etc., the thinner piece is called klaf and the thicker piece is called duchsustos.