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THE PHOTOGRAPHIC NEWS. VoL. XXVII. No. 1309.— October 5, 1883. CONTENTS. PAGE Printing on Gelatino-Bromide Paper 625 The Action of Electric Light upon Colours 626 Marey’s Photo-Physiological Studio 626 A Range-Finder on the Camera 627 Notes by a Peripatetic Photographer 628 Photo-Lithography and Photo-Zincography. By Major J. Waterhouse, 630 A Dictionary of Photography 630 Patent Intelligence 633 PAGE A New Form of Selenium Cell, with some Remarkable Electrical Discoveries made by its Use 634 Solid and Liquid Illuminating Agents 634 Stereoscopic Transparencies applied to Portraiture 635 Utilization of the Sun’s Rays for Warming and Ventilating G36 Correspondence 637 Proceedings of Societies 638 Talk in the Studio 639 To Correspondents 640 The Photographic News Registry 610 PRINTING ON GELATINO-BROMIDE PAPER. We have frequently noticed, when conversing with amateurs on the splendid scenery of this or that holiday resort, how often they are in ecstacies over the quality of some nega tives secured on the occasion of their last visit with a shutter of their own construction, differing in principle from anything yet published, or some especially good and rapid plates of their own make. So great are the praises bestowed on these negatives, that one is often tempted to enquire whether the author is likely to catalogue the results at the next exhibition, and thereby enable friends to admiie or criticise his treatment of the subjects. Sometimes we say, “ Could you show us some prints from these negatives?” But the reply is invariably, “I have never taken any prints from them. Printing is such a bother. I have no time during the day, and, of course, as you know, there is not light enough in the evening; of course they will bo printed some day, and you shall have copies.” These and sundry other excuses, perhaps pardonable with a few, are in the majority of cases more difficult to substan tiate than the difficulties attending printing by any of the known means; and we have no hesitation in saying that among that vast army of photographers—i.e., the amateurs some hundreds of plates exposed during the season never find their way to the printer, not because they are faulty negatives, but because printing is a bother. Granting that the excuses have some slight resemblance to fact, and oppor tunities do not occur to utilize daylight, there is no valid reason why proofs could not be taken by other means than direct printing in daylight. Those who have the oppor tunity to make use of the electric light will find an arc lamp with suitable reflector very useful for the purpose. In a recent experiment it was found that at a distance of 28 inches, negatives required only one-third longer to produce good silver prints than on exposure to diffused daylight. Arc lamps are not found in every house, therefore we wish to bring prominently before our readers, and more especially our amateur friends, the method of printing, direct from the negative, on gelatino-bromide paper, afterwards deve loping with ferrous oxalate solution. By this means the impact of light need be only of the weakest character ; just a few seconds to a gas jet or paraffin lamp usually suffices for negatives of medium density. An approximate time necessary for negatives of varying density can soon be a-cer- tained by a few trials, only it is a mitter of importance that the distance selected from the source of light, for the pur pose of making the exposure, should always be taken into consideration when calculating the time required. It is a well known fact that the power of light decreases in the exact ratio as the squares of the distance increase from the source of illumination, Thus, if the exposure necessary for a given negative, placed exactly one foot from a batswing burner, is known to be five seconds, the same negative placed twenty-four inches from the same source of light would require twenty seconds. It is scarcely necessary, or perhaps desirable, that we should give a lengthy description of the operations, because they are so very simple that the whole can be put in a very few words. To the uninitiated, we may say, the paper being very sensitive to actinic rays, only orange and ruby (or other non-actlnic) light may be admitted to the paper, before and after exposure under the negative, or, indeed, until after the print is in the fixing bath. After the paper has been exposed in the printing frame, it is taken from under the negative and placed in cold water, and soaked two or three minutes ; the excess of water is then poured off as much as possible, so as not to dilute the developer to any appreciable extent, and freshly mixed ferrous oxalate solution applied. In less than a minute the picture will appear, gradually gaining strength until fully developed. The time required to attain the full detail may be five minutes, more or less, dependant upon exposure, rapidity of paper, as also temperature ; when the picture is fully out, it is slightly rinsed, and fixed in the ordinary hyposulphite of soda bath, used at the same strength as recommended for fixing albumenized paper prints. Although the prints will appear fixed in three or four minutes, and may be examined in an actinic light, it is safer to put them again into the fixing bath for ten minutes ; after which they are washed in a running stream of water for a few hours; then passed two or three times through an acid bath, similar to one of those recommended for clearing the shadows of dry plates ; washed again for an hour, dried, trimmed, mounted, and rolled in the usual manner. It is generally considered that prints produced by the means we have described are more permanent than ordinary silver prints ; but they lack the warmth of tone and trans parency which silver prints possess in such a high degree. Still the neutral tint obtained is very pleasing, and sought after by many. We have on a former occasion published iu these columns the method of preparing gelatino-bromide paper; but as it is now, and has for some time been an article of com merce manufactured on a large scale, and of excellent quality, only those who have time at their disposal will care about the trouble of making their own. Improvements could be made, and no doubt will be, in the direction of greater transparency ; but as an expeditious and easy method of printing, either in the evening by artificial light, or during the day, this process is worthy of serious con sideration by amateurs etpecially, as well as their pro fessional brethren.