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THE PHOTOGRAPHIC NEWS. EDITED BK T- O- HEPWORTH, F.C.S. Vol. XXXV. No. 1709.—June 5, 1891. CONTENTS. PAGE Some Notes about Clouds 409 Optical Lantern for Projecting Pictures of Moving Objects 410 Perspective in Photography. By W. H. Wheeler 411 The Actinometer as a Guide to Exposure 412 Photography in Germany. By Hermann E. Gunther 414 Proposed Affiliation of Photographic Societies 415 Notes 416 Archaeological Photography 417 PAGE Edison’s latest Invention 418 Moonlight Photography. By E. B. Luce 419 Photographic Methods of Obtaining Polychromatic Impressions. By Leon Vidal 419 Patent Intelligence 420 Correspondence 420 Proceedings of Societies 421 Answers to Correspondents <24 SOME NOTES ABOUT CLOUDS. In the early spring, when the light is at its best, and when showery weather alternating with brilliant sun shine is the order of the day, it is comparatively easy to secure clouds in the same negative as the landscape, and it need hardly be pointed out that this is an advantage that one cannot value too highly. When such clouds are present in the negative, it is too often the case that they are buried in the film during development. When they first show themselves in the early stage of that operation, the photographer is delighted, but too often leaves them to take care of themselves while the details of the landscape below are unfolding themselves. In nine cases out of ten the sky will, under such circum stances, become so dense that clouds and what should be open space are merged together in one black mass. If, on the other hand, the photographer will take a little trouble, this destructive action can be easily stopped. When the sky first shows itself sufficiently to discover cloud-forms which are worth preserving, let the negative be lifted from the dish and well washed under the tap. Now hold it so that the sky is downwards, and, with a camel-hair brush charged with bromide solution, paint the surface of the sky, just as if you were laying-in a water-colour tint. Water-colour artists frequently paint in their skies while the picture is inverted, so that the colour shall not stray where it is not wanted. The inverted position is recommended here for the same reason with regard to the bromide solution. Now place the negative once more in the developing bath, and the landscape portion can be coaxed out without any fear of blotting out the clouds by over-development. There are numerous shutters which are so contrived that the sky portion of the picture gets but a fraction of the exposure which the landscape receives. Leisk’s sky shutter is a clever contrivance, and one which acts well in securing this end. The use of isochromatic plates with a yellow screen is also a great help in securing printable clouds in negatives, with the dis advantage, however, of a somewhat protracted expo sure. Some photographers make use of a sky-shade outside the lens hood for shielding the sky from the negative during the greater part of the exposure, and these sky-shades are of various designs, as anyone can see for himself by referring to the photographic annuals for past years. One writer, we remember, recommends the use of a ruby glass backing to the dark slide, so that, with head under the focussing cloth, one can see the amount of shading to give to the lens in order to mask the sky properly. It is obvious that most of these devices are only applicable to open views and landscapes where there is a visible horizon, that is, a plain line of demarcation between the sky and the rest of the picture. But in seascapes, where the whole of the picture, sky and water, is equally illuminated, no dodging is really necessary, for a very quick exposure will secure clouds and waves at the same instant, and without the least difficulty. In photographing cloud effects, one is apt to be led away by the beauty of the colouring. A beginner in photography generally makes this mistake with every subject which presents itself. He sees on the ground glass screen a brilliant blue sky embroidered with fleecy clouds, purple hills in the distance, relieved, perhaps, by brilliant green trees, and grass bespangled with cowslips in the foreground. “ What a lovely effect 1 ” thinks he, and he takes a photograph, only to find out, later on, what a mistake he has made in supposing that such a view could make a satisfactory picture in monochrome. But more experienced eyes are apt to be deceived in this way by the wondrous colouring of cloudland, and forget that they must study only form and light and shade. A man who is colour blind would probably make the best photographer of clouds, and an engraver, used to shutting his eyes to colour, would do as well. It is pointed out in most of the text-books that the photographer, if he print in a sky from a separate nega tive, must be careful to see that the direction from which the clouds are lighted agrees with the direction of the light which illuminates the landscape to which they are to be wedded. This is a very tiite remark to