Colour and Colour Theories

Christine Ladd-Franklin was an American psychologist best known for her work on vision. Although she earned a Ph.D. from Johns Hopkins University in 1882, it was not granted to her for more than 40 years because of the university's longstanding policy of not conferring degrees on women.This experience impelled her to campaign for equal access to education for women. Ladd-Franklin formulated her theory of color vision while teaching at Johns Hopkins and Columbia universities, where her interest in mathematics extended to the investigation of the horopter---the locus of all points in the field of vision that fall on corresponding parts in the two retinas. Her experimental work in color vision extended the hypothesis of the German physiologist Ewald Hering regarding color perception in that it demonstrated that black-white vision is the most primitive form of color vision. She continued to develop this theory for four decades.