The Black Hours is a Gothic, Medieval, Vellum, Pigment Painting created from 1460 to 1470. It lives at the The Morgan Library and Museum in New York. The image is available via Institutional Open Content, and tagged Books, The Gospels and Meditations. Source
This devotional has over 121 individual sheets and is called the Black Hours because of its black bacground. It was created in Belgiam and now lives at the Morgan Library in New York City.