Chlorophyll comes from the Greek words meaning "green leaf." Most plant cells contain yellow, orange, and red pigments, but these are obscured by the green pigment known as chlorophyll. It is in autumn, when woody plants stop producing chlorophyll, that the other colors become visible.

Chlorophyll was first isolated by French chemists in 1817. Pierre-Joseph Pelletier and his research partner Joseph-Bienaimé Caventou (1795-1877) extracted chlorophyll from green plants, but were unable to find any immediate use for it. Pelletier and Caventou were more interested in substances that could be used as medicines and later discovered such drugs as brucine, quinine, and strychnine.

About fifty years later, scientists learned of chlorophyll's role in plant life. Although Dutch scientist Jan Ingen Housz had described the process of photosynthesis in the late 1700s, no one knew exactly how green plants converted sunlight to food. In...