Here is a photo of a Renaissance era printing press. Each press is manned by a team of at least two journeymen, aided by an apprentice. One journeyman would fit the frame, or forme, filled with type set by the compositor into the tray and ink the forme with large, handled balls. The other would lay dampened paper over the inked forme, slide the tray under the screw, and turn the screw to lower the plate onto the paper and make an impression. The wet page would be hung to dry and the process begun again. An average size printing shop would have three presses in operation, a large operation five to six. One to two compositors, or typesetters, would fill the formes for each press; a proof reader would check the initial pages drawn from each forme. The compositor, and especially the proofreader, were often highly educated men, familiar with classical languages and literature.
The printing shop at the Sign of the Fountain in my novel is a small shop with two presses and one compositor. Since her godfather owns the shop, Jollande is permitted to work as a proofreader; Nicolas Vernier, a court poet working undercover to spy on the shop's activities for the Queen, assumes the role of compositor. Good thing the paper's damp, because sparks fly as these two spar over spelling.