Leonard T. Troland

Leonard T. Troland was born April 26, 1889, in Norwalk, Conn., U.S.A. He graduated in 1912 from the Massachusetts Institute of Technology with a degree in biochemistry. He then studied psychology at Harvard, where he obtained a Ph.D. in 1915. He worked for a year as a Harvard Travelling fellow at the General Electric Nela research lab. He served as a member of committees of the National Research Council on vision and aviation psychology. At Harvard, he gave advanced courses in psychology, and he followed up his 1926 book "The Mystery of Mind" with "Fundamentals in Human Motivation" in 1928. At the same time he was chief engineer of the Technicolor Motion Picture Corporation of California and was appointed Director of research at Technicolor in 1925.

He was elected to serve as president of the Optical Society of America from 1922 to 1923.

At just 43, Troland died in May 1932 after falling off a cliff while out hiking. He gave his name to the troland (symbol Td), the unit of conventional retinal illuminance. It is meant as a method for correcting photometric measurements of luminance values impinging on the human eye by scaling them by the effective pupil size.