The Optical Lantern and Cinematograph Journal (Nov 1904-Oct 1905)

THE OPTICAL LANTERN AND CINEMATOGRAPH JOURNAL. 177 folding partition 7. The post card 13 to be viewed is supported against the triangular part, and by narrow strips 14 attached to the part 4. In appearance the envelope stereoscope, when open for use, is not unlike to the cabinet stereoscope sold by Messrs. W. Butcher & Sons, of Camera House. Transposing Film Negatives. Amateurs having no special appliances for making stereoscopic transparencies, will find the following plan simple and satisfactory : — Draw a diagram as hereunder, where a, b, e, d, and e, f, g, h are of the size that the finished transparency is intended to be and ia, tit, vu, dp are not more than half an inch long. Fix the right hand half of the negative, with the film upward, above a, b, c, d, so that the portion of the picture intended to be retained will lie exactly within that rectangle, and cut the negative along the line i, a,j, k, I, b, c, in, n, 0, d, p, q, r, i. Then place the left hand half of the negative so that the part which is to be retained may rest over e, f, g, h ; fix it there, and cut it in the same way as the right hand half. Then place a piece of clear transparent celluloid over the diagram, and cut slits in it &\.jb, es,ft, vg, hx, oc, dq, and ra, and insert the tags on the two halves of the negatives into these slits. If the negative is very dense, it may be impossible to see some parts of the lines in the diagram through it, but in that case their position can be easily ascertained by the projecting lines ay, bz, etc. The celluloid is tough enough to be used a number of times by removing the negatives as they are printed, and substituting fresh ones. Recreative Stereoscopes. In a recent issue of the Photo-Revue (Paris), Ch. E. Benham describes a novel method of producing stereoscopic harmonographs. Briefly, the method is this : At the juncture of the two horizontal arms coming from the upright pendulum rods, a pin is pivoted, which in the ordinary way serves as the tracer of the design. On the top of this pin a silvered bead is fixed. The apparatus being set in motion, the bead is, of course, made to move in a corresponding path to that taken by the pin point resting upon the drawing surface, which may be a glass plate lying horizontally. An ordinary stereoscopic or twin lens camera is set up at a suitable distance from the oscillating head. The image of the bead is reflected from an horizontal mirror through the lenses of the camera, the operations being conducted in a dark room, and the bead suitably illuminated. Hence the only object visible to the camera is a brightly illuminated point on the bead, which is seen in the mirror. The luminous point which is received on the sensitive plate in the camera leaves its impression, as it is made to oscillate, thus tracing dissimilar harmonographic designs. As the movement of the bead is followed by the two lenses from their respective view points, their axes being directed toward the mirror, the pictures are not exactly alike ; and when viewed, combined in the stereoscope, have all the appearance of exquisite wirework floating in space. ^» Stereoscopic Negatives for Producing Coloured Photographs. In the Patent Journal for April 19th is an abridged specification, No. 28,798, as follows : — Producing Coloured Photographs. — Sub-divided coloured stereoscopic negatives are taken through parti-coloured screens, the patterns of which are differently arranged. In line screens, the lines of one screen are at an angle to those of the other screen. It is difficult to understand the exact nature of this invention from the scanty particulars thus given, and stereoscopists who desire further particulars may be able to obtain them from the patentee, C. L. A. Brasseur, 10, East Fifteenth Street, New York, U.S.A.