I'm looking for a a book series (trilogy?) set in a fantasy academy about a teenage boy who is an artist’s apprentice who works with special pigmented magic paints, so that we can walk into the world of the painting.
I think he lived in the attic near a large clock? The main painting had a house that resembled a face and could talk?
I distinctly remember the phrase "Feggish rubbish" tossed around as an insult.