story identification - Magic leaves "smudges" and a sorceress becomes a book

I could use some help identifying a book I read some time in the last year or so. The book goes between two different stories:

1) A student of magic finds a book in a cave that turns out to be a person transformed into a book. The book talks to the student and they share thoughts. At some point, the student runs away, chase ensues, and at the very end of the book, he manages to travel to another plane.

2) A girl in a religious society where magic is forbidden. She is the daughter of painters. She discovers she can see magic. Falls in love with some random painter, risks performing magic to not be pregnant, does it again so she can, and is arrested and sent to some prison thing.

The common element between the stories is that magic use leaves behind a smudge of some kind that can be visible.

Any assistance is appreciated.