GB241636A - Improved method and apparatus for exhibiting images, visible by daylight - Google Patents

Abstract

241,636. Steiner, A. July 26, 1924. Photographs, producing electrically.-Apparatus for producing images visible in daylight comprises insulated conductors bunched together to form a ground on which the image is produced, an electrolytic solution covering the insulators, and means for electrically connecting certain of the conductors so as to produce electrodeposition; the conductors may be selected by optical projection or by means of a stereotype or equivalent plate. As shown in Fig. 1 conductors F consisting of hexagonal graphite prisms, insulated by a covering of asphalt on their contiguous surfaces, are bunched together to constitute one wall of a tank G containing an electrolytic liquid, and selenium cells are provided on the ends of the prisms remote from the tank. The front wall of the tank consists of a glass sheet I provided with silver wire anodes H, and the selenium cells and wires are connected through a reversing switch to a battery &c. A. Selection of the conductors is effected by an optical-projection apparatus J which projects an image of a slide on to the cells, the conductivity of each cell, and thus the rapidity of electrodeposition, varying in accordance with the intensity of the light projected on to it. The image thus produced on the prisms may be destroyed by reversing the direction of the current, and the switch for this purpose may comprise conductors C, connected together and to the cells and wires as shown, and engaged by contacts on a rotatable arm D connected respectively one to each side of the battery. Movement of the arm D from one pair of conductors C to the next reverses the direction of the currents, and the arm and projector may be automatically controlled to exhibit a succession of images. In a modification, Fig. 5, the selenium cells are omitted, and insulated wires 0 are connected to the prisms F and brought together so that their ends form a plane P. A conducting plate Q, having an image photographically formed thereon in insoluble asphalt or otherwise, as shown at Q<1>, is pressed against the plane P to control the deposition, the plate Q and the wires H being connected through a reversing-switch to a battery &c.