The spacious margin allowed illuminated decoration to be added by hand. The amount of decoration presumably depended on how much each buyer could or would pay. Some copies were never decorated. The place of decoration can be known or inferred for about 30 of the surviving copies. It is possible that 13 of these copies received their decoration in Mainz, but others were worked on as far away as London. The vellum Bibles were more expensive, and perhaps for this reason tend to be more highly decorated, although the vellum copy in the British Library is completely undecorated.