just wondering how am i supposed to know which spell schools i can use as necromancer/any other class really, sometimes it says i cant write magic on some schools but i cant find how you find out which schools you cant use

thanks in advance

Check out Planet Baldur's Gate. If you're referring to BG2, there's a table that lists the schools (with opposing schools) . Spell lists are listed [url=http://www.planetbaldursgate.com/bg2/character/spells/wizard/]Here.

Hope that helps.

General mages can use spells from any school.

Specialist mages are forbidden at least 1 school ie-a Necromancer can't use Illusion spells.

The table for forbidden schools for specialist mages are found in the Tables section (the last section) of both the BG1 & BG2 manuals.