Sofer

A sofer is trained and certified to hand-write Torah scrolls, tefillin, mezuzot and certain other sacred texts collectively known by the acronym STaM, work governed by an exacting body of Jewish law specifying the precise materials, kosher parchment prepared from a kosher animal, ink of a defined composition, and a goose or turkey quill traditionally required, and the exact form of each Hebrew letter, since even a single letter written incorrectly, touching another letter, malformed, or missing entirely, can render an entire Torah scroll unfit for ritual use until repaired by a qualified sofer. Training typically takes years of apprenticeship under an established sofer, covering not only the physical skill of correct letter formation but the extensive body of law governing every stage of the process, and a working sofer must also be skilled at identifying and repairing errors in existing scrolls, a common and ongoing part of the work given how easily age, wear or a scribe's momentary lapse can compromise a scroll's kosher status.

Modern scroll-checking software, developed to scan and flag potential letter-formation errors in an existing Torah scroll, has become a widely used supplementary tool since the early twenty-first century, though Jewish legal authorities generally hold that software can assist in identifying possible problems but cannot substitute for a qualified sofer's own trained examination and final determination of a scroll's kosher status, preserving the sofer's authority even as the surrounding verification technology has changed considerably.

Jewish law governs not only the sofer's script but the physical materials a kosher Torah scroll, mezuzah, or set of tefillin must be made from, and a working sofer needs practical mastery of these requirements alongside calligraphic skill. The parchment, called klaf, must be prepared from the skin of a kosher animal according to specified processes, and the ink traditionally combines gall nuts, gum arabic, and other components into a permanent black compound that will not fade or smear, since a Torah scroll is expected to remain legible for use over generations.

Sofrim write with a quill, traditionally a turkey or goose feather, cut and shaped by the scribe himself to produce the fine, consistent strokes the required script demands, and a single significant error, an incorrectly formed letter, a letter touching another that must stand separate, or certain kinds of omission, can render an entire scroll unfit (pasul) for ritual use until corrected or, in serious cases, permanently. Because of the stakes involved, completed scrolls, tefillin, and mezuzot are increasingly checked using specialized computer software that scans the text for irregular letter shapes and other defects, a modern supplement to, rather than a replacement for, a trained sofer's own review.