Following Alan Tyson's concept, a Paper-type (PT) refers to a specific music paper where staves have been drawn (or ruled). Therefore, its defining features are the watermark and the number and size of the staves ruled by the specific rastra. The ID of a paper type is, for example, given as PT0004_01 (Paper-type 01 using watermark WM0004 and/or the corresponding twinmark TM0004). The same sheet of paper might give rise to several paper-types, depending on the rastra used; different sized rastra will produce different paper-types indicated by the suffixes _01, _02, _03, etc.
- Paper-type ID (researchable on all pages through the General Search on the left);
- Date interval (10 years) (researchable on the Paper-types page, at the top).