A fake intaglio is a series of flat stamps of different depths where if you stamp them all on a blob of wax in the right order it mostly looks like you pressed a proper three-dimensional signet ring into it. They're trying to figure out how to take magical photographs before regular photography exists so it's kind of a rough process, they have the basic idea of how to make a sort of single-Wind
daguerreotype and then overlay eight of them to create a single image similar to something called
chromoxylography, which
also hasn't been invented yet (except in Cathay), or to project light through all of them at once like technicolour film.