Ars Magica has a core concept that each Magus writes their lab notes in an abbreviated shorthand. It is a personal style of notation which must be undone and the notes translated to longhand if they are to be easily used by others as lab texts. This is typically done by the Magus taking additional season or so, or by somebody also very familiar with the Magus’s style – perhaps their lab assistant, an apprentice, or even a familiar. I think that a person can learn the style of another magus and then be able to translate for them, once a hand-waved amount of exposure is performed. That could be represented as time working with the Magus or time deciphering their style.
However if a magus wished to write the lab notes longhand in the same season as the magical activity, what penalty to lab productivity would be incurred to the lab total?
I ask as sometimes a magus can perform a lab activity easily and will have capacity for additional effort; but no real valuable mini-project to add to it.
I think it would take a significant amount of additional energy to document correctly as you go, correct for changes, and the additional scribing overhead would act as a negative influence to the efficiency of the work. On smaller projects it is probably easier, and in complex projects it might add so much time it is not worth it.
As such I’d say add one quarter again the difficulty of the lab totals to the project.
e.g. A project with a target difficult of 20 becomes 25, and the magus must try to complete the project as normal. If the magus has enough of a lab total to still complete the work in a season then well and good, otherwise it takes them into the next season. It is then a balancing act for the magus to see how they wish to conduct the work. For small projects it makes a kind of sense, which meets the balance I think is suitable.
In terms of exposure I’d say it takes 5 seasons of shared lab work to learn a magus’ shorthand. Those who know it will be able to translate well.
And yes, some games will just say stick to the rules as written, you can’t do this. Accepted without argument, but I think this makes a lot of sense.