Learned Magicians produce lab texts the same as Hermetic magi do, when inventing charms, amulets, and chartae. However, I'm not actually sure what the point of doing so is in the case of chartae. One can reasonably assume that a lab text for an amulet would have the same benefit as a lab text for a Hermetic charged item, letting you get a lot more charges out of it, but chartae get their full effects immediately upon creation and you just need a sufficient lab total to make it happen. So is making a lab text for a charta beneficial to the Learned Magician in any way? (Obviously it's beneficial to any magi looking for sources of Insight, but that's besides the point.)
Seems like it's about useful as lab text for hermetics binding a familiar, which is to say, none.
Okay, fair point, I actually forgot that Hermetics produce familiar binding lab texts. Lol.
In principle you might exchange lab texts to enable creating charta beyond the ability of the other leaned magician...
I don't think that would work, unless the Lab Text removes the "divide Lab Total by half" aspect of Chartae for the person working off it. (In which case they might actually be beneficial to people using Experimentation to achieve sufficient lab totals for their chartae as well.)
It might be useful when repeating the charta in a more hostile aura- for example make your initial charta in a magical aura then use the lab text in a divine aura.