Moving Picture News (Jan-Jun 1912)

14 THE MOVING PICTURE NEWS rotating screen, will project an image in natural colors on the screen. By using lenses made up of three different colored sectors, the three-colored screen may be dispensed with both in the camera and magic lantern. Remarks: Lenses made up like this do not pass actinic light but safe light, therefore, it is impossible to take photographs with such an instrument. To swirl three difTerent color screens in front of one lens to make one negative, as here suggested, serves no scientific purpose, but it shows that the inventor desired to adapt Ives' system without understanding it. By the additive method of color photography, it is required that one negative should be taken through each color filter, that is, three negative color records are obtained. To take three color records with this inventor's apparatus is not possible, because there are no opaque spaces to allow the plate to be changed between the separate exposures, nor does he require the photographic film to be sensitized to all colors; red or green light could, therefore, not act on the ordinary brom-silver gelatine film. Specification 6202. March, 1899. Lee, F. M., and Turner, E. R. Relates to kinematograph apparatus for taking and exhibiting photographs of moving objects in their natural colors. A rotary color screen being mounted on one axis. This screen is made up of a green, a red and a blueviolet sector of glass, each pair of sectors being separated by opaque bands (see Fig. 3). The velocity ratio between the screens, and the color sensitive film is such that each picture on the ribbon is taken through a color sector of dil¥erent color. The positives of the various Specification 249. January, 1902. Vaughan, "W. F. Relates to a kinematographic apparatus for producing pictures, and exhibiting them in natural colors. The photograph on the ribbons are taken in series of three. The colored screens form the three sectors of a rotating disc. An endless band shutter, with apertures of different width for the three colors, to regulate the exposures, revolves on pulleys. Remarks: This is simply an exposure regulating device, and could not be worked without a license from Lee-Turner. Specification 3729. February, 1903. Fumeaux, B., and Davidson, W. N. A camera, by means of prisms, produces three independent images for use in tricolor photography. The camera may be used for optical projection. The prisms are placed in front of the lens. Remarks: The invention is practically of no use for a three-color system, but with the system as shown in the illustration two color results have been obtained, and were shown in May,' 1904, in Paris. To guard against double reflections and ghost pictures the objects have to be photographed before a non-reflecting dark background. It is also to be noted that absolutely sharp pictures cannot be obtained by the aid of such prisms. If the pictures are taken, say at 20 feet distance, then the projection has also to be at 30 feet, or the picture would not superpose. It is also advisable to put a light screen, LS, in front of the lens, to further separate the light cone. The light intensity as affected by a prism is shown in F (Fig. 4). color sensations may be exhibited singly in rapid succession, or two or all of them may be superposed. Remarks: This invention allows also the use of twocolor projection, and the specification clearly states superposition by rapid succession — i. e., duping the eye by persistence of vision. The inventor does not claim originality or property in arriving at this illusion, he could not suggest it quicker than by Motor 3232, 1897 above. The inventor based his hopes of success on a very rapid lens, Fl, but the then known sensitizers scored against him. The possibility arrived only in 1902 with the introduction of orthochrom, a color sensitizer which enabled a rapid exposure through an orange-red color filter The exposure can now be made as 3 to 1, through the orange-red or blue-violet color filter, against a former ratio of 50 to 1. Specification 23863. November, 1899. Davidson, W. N. L. The rotary color screens holding the different colored sectors are here mounted eccentrically in front of the usual kinematographic revolving shutter when taking the negative color records The positive color records are dyed in the respective film colors, thus obviating rotating color filters when projecting. Remarks: The negative color records, are, therefore, taken with a similar screen as Lee-Turner's. Specification 7179. March, 1904. Davidson, W. N. L. This is a kine-mirror box, which by reflection superposes two or three color records, when such are to be projected in superposition on the screen. Remarks: If ordinary plate glass mirrors are used, double reflection is set up by such mirrors. Substituted faced mirrors soon tarnish. The invention enables the projection of color records placed side by side and obtained by wedge shaped prism (Fig. 5). Specification 27418. December, 1904. Davidson, W. N. L. Placing the prisms point to point behind the lens is an improvement on 3729, 1903. The formation of double pictures is thus avoided, and no special background is required. The light dispersion to the focus is here also unequal, as shown in F. If two such pictures are superposed with the aid of color filters, then the combination picture will show more red on one side and more green on the opposite side. This is a defect inherent in all pictures formed by reflections through wedge shaped prisms (Fig. 6). Specification 322. January, 1905. Pfenninger, O. Placing the two prisms at the crossing point of the light rays in a lens combination is claimed as the best position. Remarks: This formation is undoubtedly the best, but