Jacobus Jan Koeman was a graphic artist, painter and illustrator who for some time made refined illustrations for the well-known Verkade albums, for instance the My Aquarium album. This laid the foundation for his later watercolors. The painted oeuvre of Jac. J. Koeman includes landscapes, flowers, still lifes and portraits. Originally trained as a craftsman, Koeman worked as a sculptor and ceramist as well as a painter.