The pigments of the colors decorating the room of the seigneurial dwelling of Guédelon were drawn from the ochres, sands, and earth of the nearby quarry. Like the thirteen other workshops surrounding the castle, the color factory is intimately linked to the nearby environment. The finer the pigments, the longer they stay on the walls and the more beautiful they look. The apprentices grind them for a long time, following the recipes that have made it possible to decorate the walls of castles and abbeys since the 13th century.