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|Gabriel Jonas Lippmann
pioneer in color photography
Gabriel Jonas Lippmann was born to French parents in Hollerich, Luxembourg, on August 16, 1845. His family moved to Paris when he was three, and he received his early education at home, primarily from his mother. He entered the Lycée Napoléon in 1858, but was not considered a good student because he would only focus on the subjects that interested him and ignore everything else. He entered the École Normale in 1868, but chose not to follow the prescribed course load that would have allowed him to take the examination to become a certified teacher.
In 1872, Lippmann invented the capillary electrometer, an instrument which measured very small differences in voltage by the movement of a mercury "bubble" in a capillary tube. The device was used in early electrocardiographs, and, in 1873, got him appointed to a French government mission to explore better methods for teaching science. The mission took him to Germany, where he worked with Gustav Robert Kirchhoff at the University of Heidelberg, where he passed his doctorate in philosophy examination summa cum laude in 1874.
Lippmann's capillary electrometer
Lippmann submitted his Ph.D. thesis on electro-capillarity to the Sorbonne on July 24, 1875, was named to the Faculty of Science in Paris in 1878, was appointed Professor of Mathematical Physics in 1883, and became Professor of Experimental Physics in 1886. He was subsequently appointed Director of the Research Laboratory, which was later transferred to the Sorbonne, and he retained this position until his death. He became a member of the Academy of Sciences in 1886, and served as its President in 1912. In 1888, he married the daughter of writer V. Cherbuliez.
Lippmann first developed his theory of a process for the photographic reproduction of color in 1886, but its practical execution proved difficult. He was finally able to describe the process to the Academy of Sciences in 1891, but the photographs he presented were somewhat defective due to varying sensitivity of the photographic film. He continued to revise the process until 1893, when he was able to present color photographs taken by Auguste and Louis Lumière to the Academy that displayed perfect ortho-chromatism. He published his complete theory in 1894.
color photograph taken using Lippmann's method in
Lippmann's technique was based on the principle of interference, the combining of different light waves arriving at the same point simultaneously (this is what makes colors appear in otherwise clear soap bubbles). To receive the image, Lippmann used a glass plate coated on one side with a light-sensitive emulsion (a mixture of gelatin, grains of silver nitrate, and potassium bromide). In the camera, the emulsion side of the plate faced a plate holder coated with mercury, which acted as a mirror. When the camera lens was opened, light was reflected from the objects in the lens's field of view through the lens to the emulsion-coated plate and through the plate to the mirror; the various wavelengths of this light corresponded to the various colors of the objects in the field of view. The incoming light was then reflected back into the emulsion by the mirror. When the incoming light waves and the light waves reflected by the mirror met on the surface of the emulsion, they created interference patterns in the silver grains of the emulsion. These patterns were then fixed on the plate by chemical baths. When the plate dried, the interference patterns reflected light in various wavelengths corresponding to the original colors of the photographic objects. Although Lippmann's process was an important experimental milestone, it proved impractical in photography because exposure times were too lengthy, the image had to be viewed at a precise angle to a light source, and it could not be reproduced. Despite the limitations of Lippmann's process, it led to his being awarded the Nobel Prize for Physics in 1908.
In addition to the capillary electrometer and color photography, Lippmann also evolved a method of eliminating the personal equation in measurements of time, using photographic recording; studied the eradication of irregularities of pendulum clocks, devising a method of comparing the times of oscillation of two pendulums of nearly equal period; carried out research in piezoelectricity and seismology; and invented the coelostat, an astronomical tool that compensated for the earth's rotation and allowed a region of the sky to be photographed without apparent movement. In 1893, he became Marie Sklodowska's faculty advisor. He was so impressed with her that he let her use his laboratory for her thesis work, and even helped her find sources of support. He was also the one who introduced her to Pierre Curie, who was also one of his students.
Gabriel Jonas Lippmann died at sea on July 13, 1921, while returning from a mission to North America led by Marshal Fayolle.
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