Today we stand on the threshold of understanding neurophysiologically how the visual cortex achieves this colour constancy that is so essential for our survival in our world of frequently changing colour temperature. It might be that aphorisms, and dominated his approach to science. For example, he was very impressed with the recent advances in cortical neurophysiology by Hubel & Wiesel and Zeki and he often flew to London to sit in on Zeki’s experiments. He had also studied them, for in conversation he often quoted early workers in discussion and he had an extensive knowledge of the current literature. Why did Land not quote early workers and try to relate them to his own research? He certainly had a very extensive personal library that contained many books on visual science. ![]() Land’s contribution was to formulate a precise model - the retinex theory - that could relate these perceptual phenomena to neural events in the brain. This is analogous to brightness constancy, the processes of light and dark adaptation that make us unaware of the absolute luminance of a surface unless we use an exposure meter to adjust our camera. The perception of colour was not simply a matter of the physical nature of light, and our sensation of the hue of reflecting surfaces is much more stable - less dependent on the illuminant - than we are normally aware. Thus, Thomas Young had noted in 1807 that white paper still looks white even when illuminated by the red light from a fire, and earlier still, Gaspard Monge (1746-1818) had demonstrated that patches of colour may dramatically change their appearance as the result of the colouration of their surroundings. To them, the dramatic demonstrations that made him appear in the popular mind as an iconoclast challenging accepted ideas were merely vivid examples of the phenomenon of colour constancy that had in essence been described 150 years earlier. ![]() Land’s rather dramatic demonstrations to the public of his views on colour theory and his lack of references to earlier work in the field generated excessive criticism from the ‘colour establishment’. Novel equipment, using these colour systems, has also been widely exploited, including versions where the colour photograph develops in daylight.Ī Historical Assessment of Land's Colour Theory All of this required a team of first-class scientists and technicians that he led with great success. He mastered the complex physicochemical science that gave neutral or coloured, continuous-tone, instantaneous photographs. In the field of photography, Land developed the cameras and associated special films that produce almost instantaneous dry pictures directly from the camera. The trade name ‘Polaroid’ has become the accepted generic name for these sheets. Such devices are widely used today in liquid crystal displays (LCD), in sunglasses and in scientific and medical research. In the field of polarized light, he was responsible for the invention, development and efficient commercial production of the first sheet polarizers, for a sequence of subsequent polarizers, and for the theory and practice of many applications of polarized light. Land’s achievements spanned the disciplines of art, science, technology and commerce. He has had few peers in the advancement and application of natural science to everyday life. ![]() He mastered the art of giving the people what they wanted at a price they could afford. The Polaroid Corporation, which Land founded, may continue to do so for many more. He has had an impact on the lives of many millions of people and has provided large-scale employment in many countries for over five decades. LAND was distinguished for his inventions and contributions in the fields of polarized light, photography and colour vision. Campbell, F.R.S.† Summary of AchievementsĮDWIN H. While not an official biography, the following is reprinted with the kind permission of the Royal Society.īiographical Memoirs of Fellows of the Royal Society, 40, 195-219 (1994).Įlected for Membership Royal Society, 1986īy F.W.
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