There's something about watercolor painting that seems a perfect fit for a summer exhibition – perhaps the watery way the paint absorbs into the paper is as cooling as a dip in a refreshing lake.

Even though most of us played with water-based paint in school, it is nonetheless intriguing to learn that "watercolor paint is a finely ground pigment suspended in an aqueous solution of gum Arabic, made from the sap of the acacia tree." This all comes to life in Painting on Paper: American Watercolors at Princeton, on view through Aug. 30 at the Princeton University Art Museum.