The Optical Magic Lantern Journal (November 1893)

Arter the publication of our last journal we ; learned that the illustrations sent in. with the article on page 147 were reproductions from the “Cyclist Annual’ of 1885, the copyright of which belongs to Messrs. Iliffe and Son, and we hereby tender our apologies to that firm. We have communicated with the writer of the article in question, who also expresses his regret, he not having been aware of the previous publication by Messrs. Iliffe of the illustrations. Mr. W. I. CuHapwick was, we understand, the first person who published the method how to ascertain the contents of a cylinder of compressed gas, viz. :—-By dividing the number of atmospheres indicated by the number of times that the capacity of the cylinder in feet was coutained in 120. A TRANSLATION of Dr. Eder’s ‘‘ Handbuch der Photographie’ is now appearing in the Amateur Photographer. Dr. Iider’s book is recognised as a standard on emulsion photography. be + At WHEN on a recent trip to Chicago, Mr. Archer (Archer & Sons, Liverpool) took some charming views in and about the exhibition. received a few prints from the negatives, and learn that the slides are being made as fast as possible. Mr. Ropert H. Crarx, of Royston, Herts, finding it somewhat difficult to keep up with his numerous and increasing business in lanterns, slides, &c., has rebuilt a portion of his premises. These have just been completed, and Mr, Clark is now prepared to supply lanternists with anything and everything on the shortest possible notice. ———— ‘0: ——. Judging Lantern-slides Exhibitions. at At a meeting held recently, at which Mr. Andrew Pringle and some other well-known judges at photographic exhibitions were among those present, the wise resolution was passed that no awards should be made in relation to lantern-slides without projecting images of them upon the screen, the decisions to depend upon the appearance of the projections. With a, colourless slide, presenting nothing but pure black and white, this may not be so necessary; but when colour comes into play it is exceedingly necessary. lor instanee, the more We have j The Optical Magic Lantern Journal and Photographic Enlarger. dclicate purples which make some slides look excecdingly beautiful by daylight, are quite lost when projected by a light rich in yellow rays, such as that from an oil lamp; and with the limelight the result is not much better, that light, despite its brilliancy, being poor in true violet rays. The electric light does most justice to this class of slide; the magesium light also would be good were it practically available. The question ought farther to have been decided by the judges, whether the particular light for use with which the slides were intended should not be used in the judging. #or instance, in ! the course of some experimental researches in relation to the obtaining of images of different colours with photographic transparencies, a person known to us has obtained rich tones by one method, in which it hag not yet been possible to avoid a pale primrose stain over the whole slide, something to the eye like that presented by photograplis taken by the primuline process. ‘he tinge is such that with an oil light it would scarcely be perceptible, if at all, yet would add to the warm appearance of the image on the screen, but with the limelight would probably be recognised as yellow. ; There is another point to be considere¢— namely, that as purple images when projected upon the screen by ordinary lights appear to be of some other colour, it is impossible to tell by inspection of such slides in daylight exactly what that colour will be. In some cases it is rich, in others it is poor. The new plan of judging will be a boon to disappointed competitors, because in daylight they can point out to their friends their own slides, and how much better they look than those which have taken prizes. This raises the further problem—Is it judicious to place lantern-slides on public view by daylight at exhibitions, in those cases in which the awards bear relation to the colours of the slides as seen upon the screen ? —:0:—— The Problem of Inexpensive Stereoscopic Projection. A DIFFICULTY in the way of the utilisation for public purposes of stereoscopic lantern projections, in which the effects are produced by means of polarised light is, that an analyser has to be placed in the hands of every person present; this, in any case, means a somewhat large first outlay on the part of the exhibitor, and in the case of a public exhibition, in which six or seven hundred persons are admitted on payment, there is, unfortunately, reason to fear that in the present state of society some of the