| Nixitur |
Anyone have any ideas with this?
Since the only rule about taking up pages in spellbooks is for spells, the only interpretation that I can gather from the rules as written is that the preparation rituals take up no space at all. You can houserule what you want, of course, but since many preconstructed spellbooks are actually several books, they're already heavy enough.
Edit: Although now that I think about it, I recall a discussion about the weight of things that aren't listed in the rules and obviously, just because something isn't listed doesn't mean it's weightless. Similarly, just because the page cost for preparation rituals isn't listed doesn't mean it's zero. Same goes for the "notes on the caster’s other research, personal diaries, naturalist sketches, or even political treatises" that preconstructed spellbooks often contain.
So, bottom line, it comes down to GM decision and flavor. If the previous owner of the spellbook was a very neat and tidy person, maybe the ritual only takes up a single page. If the ritual is mixed in with research on the ritual, a description of the caster's lunch and a scathing satire about a local noble, maybe the spellbook only has 80 usable pages. It comes down to what you think is appropriate.