Frederick Wratten
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Frederick Charles Luther Wratten (1840,[1] England – 8 April 1926,[2] London) was an English inventor.
Wratten started his career as a school teacher and organist, and moved to London in 1861 to become a clerk in the Photographic & Optical Warehouse owned by Joseph Solomon. His work there stimulated his interest in photography, and while there learned of the use of gelatin as a sensitized emulsion, and began experimentation on his own.
In 1876, Wratten invented the use of alcohol in drying gelatin emulsion and removing unwanted nitrate of silver. This process was described in the British Journal of Photography of 1877 and 1878. During the course of his experiments, Wratten formed a partnership with Henry Wainwright and in 1877 they formed a partnership, Wratten and Wainwright, to manufacture and sell photographic supplies for the collodial process and the process of forming dry gelatin. Wratten & Wainwright were the first firm in England to offer dry plates commercially.
Wratten is also credited with introducing in 1878 the noodling process for gelatin emulsion before washing, which substantially increases surface area and thus the efficiency of the process. This allowed creating more sensitive photographic plates than previously possible. In 1906 Wratten incorporated his company with his son S. H. Wratten, and C. E. Kenneth Mees as owners. Mees, a recent graduate of London University, was placed in charge of new product development, and soon introduced panchromatic plates sensitive to longer wavelengths. To allow photography using particular wavelengths of light, Mees developed dyed gelatin colored filters which were placed between the plate or lens and the subject matter. These colored filters, later known as Wratten filters, began with yellow filters dyed with tartrazine (CAS # 1934-21-0), but soon were available in many more colors. George Eastman purchased Wratten and Wainwright in 1912, to be merged with Kodak Ltd at Harrow. At approximately this time both Frederick Wratten and S. H. Wratten began working at Harrow, while C. E. Kenneth Mees moved to Rochester, New York to found Eastman Kodak's Research Laboratories.