- Casting time is increased to 1 turn, after which the spellcaster makes a saving throw vs. magic. If failed, the casting time is increased by another turn, followed by another saving throw. Repeat until saving throw is successful or spellcasting attempt is abandoned.
- The casting must be uninterrupted.
- Material components must be used.
- The spellbook containing the spell must be available to consult during the casting.
[Edit: Casting time revised 5 June 2014.]