Land , Edwin Herbert

(1909–1991) American inventor

Born in Bridgeport, Connecticut, Land began his education at Harvard but left to develop a number of commercial ideas.

His first success was a method of producing a relatively cheap filter that would transmit polarized light. The material, sold under the tradename Polaroid, was a plastic containing aligned crystals, which restrict the light vibrations to one plane. Land set up the Polaroid Corporation in 1937 in Cambridge, Massachusetts. With the onset of World War II there was an increased demand for polarizing filters for sunglasses, binoculars, and other optical instruments, and Land's company flourished.

Following the end of the war Land sought new areas to exploit. He chose photography and concentrated on designing an instant camera. Chemicals to develop the film were contained in a lead pod pierced as it was squeezed through a pair of rollers. Early instant cameras required a wait of a minute or more before peeling away the protective plastic. Land's SX70 camera, launched in 1972, ejected the print instantly for the image to develop within seconds.

Land also tried to develop a new theory of color vision that began by rejecting the old trichromatic theory linked with Newton and Young. How, he asked, does the eye cope with an excess of red in a room lit by an incandescent tungsten light? Familiar objects like green apples and yellow lemons do not appear to redden in this artificial light, despite the fact that it does not have the same spectral distribution as sunlight. How do objects retain their ‘color identity’ under a great variety of lighting conditions? It cannot simply be the responses of the retinal photoreceptors to radiant energy; also involved are high-level brain processes. Thus for Land, vision was a retina-and-cortex system, which he called a retinex system.