This is an manuscript example from the British Library. If you look closely at the right hand border (in this case the verso page), you will be able to see the uneven pricking in preparation for the ruling. Free of known copyright restrictions.
Albani (St Albans) Psalter: Initial B King Solomon English Romanesque ca. 1125 Hildesheim: Basilica of Saint Godehard, folio, 72 From oberlin.edu Art 315 Illuminated Manuscripts Week 5 Fall semester, 2006 Erik Inglis, Department of Art