Klaf
Klaf or Qelaf is the designation given a particular piece of skin. The Talmudic definition includes both the form of the skin and the way it is processed, in particular, that it must be tanned. Since the innovative ruling of Rabbeinu Tam it is primarily used to refer to parchment or vellum. It is one of the materials upon which a writes certain Jewish liturgical and ritual documents.
Description and rules
is a specially prepared, tanned, split skin of a kosher animalgoat, cattle, or deer. Rabbinic literature addresses three forms of tanned skin:, consisting of the full, unsplit hide; and and, which are the split halves of the full hide. The rabbinic scholars are divided upon which is the inner and which is the outer of the two halves. Maimonides is of the opinion that was the inner layer and that was the outer layer.The "Shulchan Aruch" rules in the reverse that was the outer layer and that was the inner layer.
There are halachic rules for the use of each of the three types of skin. According to Maimonides, Torah scrolls must be written on g'vil only on the side on which the hair had grown, and never on duchsustos. Phylacteries, if written on k'laf, must be written on the flesh side. A mezuzah, when written on duchsustos, must be written on the hair side. It is unacceptable to write on k'laf on the hair side or on the split skin on the flesh side.
Preparation
The legally required method of cleaning and preparing has been altered over the centuries. During Talmudic times, salt water and barley were sprinkled on the skins which were then soaked in the juice of . Nowadays, most processors dip the skins in clear water for two days and then soak them in limewater for nine days to remove the hair. When it is a hairless surface, the scribe stretches it on a wooden drying frame and scrapes it until it is dry. Creases are ironed out with presses. Then it is sanded until it becomes a flat, smooth sheet fit for writing. The reasons for the change in this process are lengthy and controversial. Today, a few Jewish scribes still prepare in precise accordance with the Jewish Law.Some parchment is smeared with log, a chalky substance, to make it whiter. Occasionally this is only done on the reverse. Some scribes object to the use of log as it forms a barrier between the ink and the parchment.
Uses
In Talmudic times was primarily used for and at times. Since the 9th or 10th centuries it has become more widespread to write Torah scrolls on ; however, even today, there are still groups who continue to adhere to the ancient prescription described in the Talmud, and continue to write on .Abraham ben Isaac of Narbonne, one of the Hachmei Provence, wrote the following account in his Questions & Responsa: