GB362885A - Improvements in or relating to luminescent gas discharge tubes - Google Patents

Abstract

362,885. Colour photography. CLAUDE NEON LIGHTS, Inc., 41, East 42nd Street, New York, U.S.A.-(Assignees of Beck, L. L. ; 27, Stonleigh Park, Westfield, New Jersey, U.S.A.) June 5, 1930, No. 17433. Convention date, June 26, 1929. Void [Published under Sect. 91 of the Acts]. [Class 98 (ii).] To produce white light for photography with panchromatic and orthochromatic films, the red rays from an electric discharge lamp containing neon are blended with blue rays from a discharge lamp containing mercury with or without neon or argon &c., the blue rays passing through a yellow or amber screen. Colours are not distorted, green photographing as a lighter grey than blue. The tubes operate at low voltages and high currents and have low-voltage electrodes of the hot or alkali metal types. The mercury tube may have an envelope of uranium or yellow glass or may be coated with yellow gelatine and is preferably so placed that the red rays from the neon tube pass through it and blend with the blue rays to avoid colour fringes. The two tubes may be placed adjacent or may be constructed one within the other as in Fig. 2, the intensity of the light emitted by one or both tubes being controlled by adjustable resistances or other impedances 10 in circuit with the tubes. In a modification, Fig. 3, a large neon tube 15 is surrounded over part or the whole of its circumference by mercury tubes 16 in a common reflector 18.