Books of Hours were the prayer-books of the laity, as the breviary, portiforium, or "portoos" was the prayer-book of the priest.
See below, page [230], for an explanation of the difference between "mat" gold applied as a fluid pigment with a brush, and burnished gold leaf laid over a raised "mordant" or enamel-like ground.
In point of technique these beautiful miniatures are exactly like very delicate wood-cuts, though in most cases they appear to have been cut (in relief) on blocks of soft metal, treated just as if it had been wood.
Perhaps the earliest was one issued in 1486 by Antoine Verard.
In these earliest Parisian printed Horae the backgrounds of the borders are left plain white; unlike the later ones, in which the borders have dotted or criblée backgrounds.