One need not be an ordained rabbi to serve as a sofer, but one must nevertheless absorb and deploy a great deal of knowledge and skill.
A sofer (סופר) is a scribe (the female sofer is a soferet) who transcribes onto parchment the words of sifrei Torah and tefillin and mezuzot. The acronym formed by those works is ST״M, in Hebrew letters סת״ם, pronounced “stam,” is used to represent all such scribe work (including the megillot and other holy documents as well).
To serve as a sofer, one must be religiously observant, of good character, and knowledgeable of the pertinent laws (called sofrut). Not only must one learn to do the writing, but one must learn the zillions of rules that obtain. (Okay, maybe it is only thousands of rules.) A sofer not only must be able to create, but also to check over already written texts and repair whatever is needed.
To learn the trade, aspiring soferim apprentice with those who are already established in the field. They are learning to write in indelible ink on prepared parchment with appropriate blessings and actions.
The parchment comes from the skin of a kosher animal. It must be prepared in exactly the right way, which does not involve “tanning” like we tan leather. Parchment is not tanned, it is raw. That is why we must keep our scrolls away from moisture; getting it wet would crinkle it up. The preparation begins with a fresh skin from an animal which would be kosher if one were consuming it if properly slaughtered and kashered. For this purpose, it need not be kosherly killed (no shehita necessary).
The skin has to be stripped of its flesh and blood and sinew from the inside and its fur from the outside. To loosen the fur, it is soaked in lime (the chemical, usually calcium oxide, not the fruit). (In prior days they used animal waste to change the pH of the skin.) Then it is scraped, and rinsed in fresh running water, and stretched on a stretcher to dry. Subsequently it is sanded smooth. The prepared parchment is called klaf, which technically refers to the inner layer of the skin, reached after sanding. One wouldn’t want either side of the klaf to be rough, as it might be tough to write on, or it may rub on the letters of the finished scroll.
Remember that each of the 304,805 letters in a sefer Torah must be perfectly rendered to result in a kosher scroll. Should one of the letters become chipped or faded, repairs are necessary. When such a flaw is discovered (or once it happens), the scroll is retired until it has been repaired: repaired by a sofer.
Glad you asked this question! We will study more about this topic in future columns.