Patent GB-535344-A (GB)
Title: Improvements in motion picture film for providing relief effects
IPC: G03B35/00
Filed: 1939-10-04
Abstract: 535,344. Moving pictures with relief effect. TERWILLIGER, I. M. Oct. 4, 1939, No. 27221. [Class 97 (i)] In a motion picture film giving an effect of relief to the images on projection, each frame bears a compound image of the same density and comprising two or more superimposed elemental images each of different related aspects of the scene, the images in one aspect predominating in average density over those in the other aspect or aspects, and the relative proportions of the densities of the different elemental images in a frame varying along the strip in a recurring sequence. The elemental images may be taken by two objectives at eye-distance apart, or from different view points obtained by shifting the camera in the direction of the lens axis, as described in U.S.A. Specification 2,104,779, or by the use of a movable refracting element as described in U.S.A. Specification 2,174,766. The predominance in average density of one image, termed the " dominant image, causes the projected image to appear sharp and steady, the less dense or " recessive " images taken from a different aspect giving it the effect of relief. The figures illustrate the production of one type of film, Fig. 1 representing a negative consisting of odd-numbered frames, e.g. 1 and 3, taken in aspect "A," the density " ten " of the images being conventionally represented by ten horizontal lines, and of even-numbered frames 2 and 4 taken in aspect "B," also having a density of "ten" represented by ten vertical lines. Fig. 2 shows the result of a first printing from the negative film, in which the aspect " A " images 1<SP>1</SP> and 3<SP>1</SP> are printed to a density of " six " and the aspect " B " images 3<SP>1</SP> and 4' to a density of "three." Fig. 3 shows the positive film obtained by moving the negative film one frame back in relation to the positive film and superimposing on the " B " images resulting from the first printing "A" images of density "seven," and on the " A " images " B " images of density "four." The composite images on each frame are therefore all of the same density "ten," but the images of the dominant aspect "A" alternate between densities of "six" (1<SP>1</SP>, 3<SP>1</SP>, and 5<SP>1</SP>) and " seven " (2<SP>1</SP> and 4<SP>1</SP>) those in recessive aspect " B between densities of " four " (3<SP>1</SP> and 5<SP>1</SP>) and " three " (2<SP>1</SP> and 4<SP>1</SP>). The " A " images will therefore predominate in intensity in projection, and the relative densities of the images in the two aspects vary in recurring sequence. In the foregoing example the aspect " A " images predominate in the ratio of 7 + 6 to 3 + 4, that is in the ratio 13 to 7, but the inequality may be greater or less than this, greater predominance of the dominant images giving greater smoothness but less relief effect in the projected image, and vice versa. For example, odd frames may be printed with " A " and " B " images each of density "five," and even frames with "A" images of density "six" and " B " images of density "four," giving a predominance ratio of 11 to 9. The emphasis may alternate between the two aspects, one however predominating in additive total. For example, odd frames may bear '' A " and " B " images of densities " nine " and "one" respectively, and even frames " A " and " B " images of densities "three" and " seven " respectively. In this case " A " and " B " images predominate on alternate frames, but the "A" images predominate in the sum total of the frames. Examples are also given of films in which the elemental images are in three different aspects, one form comprising a primary image in major density, a second taken in a slightly variant aspect and of lesser density, and a third in greater aspect variation and of still less density. Each frame may comprise images in two aspects only or in all three aspects. The various aspect images may all be taken on a single negative film or on separate negative films. The printing apparatus described in U.S.A. Specification 2,173,866 may be employed.