A solar color spectrum produced by a prism of carbon disulphide. Made by Michel Eug癡ne Chevreul. Chevreul (1786-1889) was a French chemist who is credited with the discovery of margaric acid and designing an early form of soap made from animal fats and salt. Chevreul was particularly influential in the world of art, since he determined that perceived color was influenced by other surrounding colors. This led to a concept known as simultaneous contrast. On this spectrum, the white lines at the letters are Fraunhofer lines. In physics and optics, Fraunhofer lines are a set of spectral lines named for the German physicist Joseph von Fraunhofer (1787-1826).