Because the ritual and practical elements of the Book of Hours were relatively standardized, the artistic expression of illustrators is a defining factor that sets each individual book apart. A Book of Hours could be several styles depending on the goals of its owner, ranging from strictly utilitarian to ostentatiously gilded. This stylization was regional. While the text only varied slightly from city to city or region to region, cultural centers began to gain visual identities. Most notable was Paris, a center for artistic production that created some of the most beautiful Books of Hours, many of which contain similar stylistic elements including large, gilded initials; red and blue patterned initials with white lines inside the colored area; red and blue line endings with white zigzags; and decorations of swirling vines and flowers around the edges of important pages. The lengths to which this kind of ornamentation went depended on the wealth of the patron and the purpose of the book, with a luxury object needing more flowery additions than something designed for daily use. In contrast to the Parisian French style, books coming out of Northern Italy tended to be decorated more simply, with more black linework than gold, flower borders and full-page images used more rarely, and initials done in one color at a time that alternated between red and blue.

Examples of text pages from Italy (far left) and France (others). The Italian page uses only red and blue, with large initials decorated through detailed yet abstract linework along one side of the page. Every line reaches the edge of the page, making this the most efficient design. The French page second from the left saves space similarly, but without the intricate linework and with the addition of gold leaf for large initials, with small linework designs inside, a barebones approach that may have made this book cheaper than the others. The next French page features gold leaf and intricate zigzag patterns to fill the end of lines, as well as marking the largest initials with flower designs along one side of the page. The French page to the far right is fancier, suggesting a wealthier patron, with the French-style line filler designs added to more initials, gold leaf added to the borders of the text box and parts of the flower design, designs that fill all four sides of the page, and the widest range of color of the four.

The careful customization of art in Books of Hours can also serve as useful visualizations of medieval life. Rather than trying to depict Biblical scenes in the Middle East, artists frequently showed ancient characters living in their contemporary landscape. The Nativity, for example, is often depicted as happening in the middle of rolling French hills, and the Flight into Egypt looks like a flight through the countryside. Shepherds and other minor characters were drawn in the clothes of the time, allowing a modern reader to get a sense of what the area and people would have looked like, especially in comparison to features like the labors of the month which had no connection to ancient times.

In addition to the city in the background, which will be repeated throughout this book, the shepherds in the foreground of a typical Terce illustration are special. They are dressed like medieval French people, not ancient Middle Eastern ones, and a woman has joined them. This woman, who also appears in front of personal prayers in this Book of Hours, is likely the owner herself, inserted into the stories!

One particularly interesting example is in a book from 1490, called "Garrett MS. 56" in Princeton's system. Throughout the illustrations, a city with pink walls and several towers is shown in the background. This city is consistent, creating a constant landscape that, while not looking like ancient Jerusalem, gives the Bible stories a concrete setting. It’s possible that this was meant to invoke Rouen, France, where the manuscript comes from! Even in non-Biblical scenes, this city plays a role; The Three Living and the Three Dead is shown happening just outside of its borders, with the living gentlemen leaving the city to hunt in the countryside.

The Flight into Egypt and The Three Living and the Three Dead are both shown occurring in front of the same city (note the three towers on the hill in the background). These scenes, set apart by dozens of pages in the manuscript, help give this book a unique identity born of the place it was made and the preferences of its artist and patron.