Aganazzar's amanuensis

Aganazzar's amanuensis was a spell that added a dozen blank leaves to a targeted book.

Effects
When cast, the targeted book gained a dozen additional leaves (meaning 24 pages, one for both sides of each leaf) made from the same material as the pre-existing ones, and placed a hovering ink-dipped quill above them. The quill would stop hovering the moment it was touched by a living being.

It was said by Elminster that spells written upon pages created through Aganazzar's amanuensis were prone to instability, and that this instability worsened over time and further pages added with the spell.

Any pages added with this spell increased a book's weight the same way nonmagical pages would.

Components
This spell required and consumed a quill, a wooden stick, and a cured and cleansed animal hide in its casting.