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THE PHOTOGRAPHIC NEWS. Vol. XXIX. No. 1379.—February 6, 1885. CONTENTS. PAGE Effects of Low Temperature The Wenham Gas Lamp Photo-Tint Blocks by Mr. Dallas Use of the Royal Arms The Intensificaticn of Gelatine Negatives. By II. Chapman Jones Notes from New York Review Hydroxylamine as a Developer for the Rapid Printing Paper. By Arnold Spiller 81 82 83 83 83 84 85 85 PAGE A Dictionary of Photography 86 Notes 87 Patent Intelligence 89 The Preparation of Hydrochloride of Hydroxylamine. By Arnold Spiller 90 On the Rapid Printing Paper. By Leon Warnerke 90 Correspondence ; 91 Proceedings 92 Talk 95 Answers to Correspondents 96 EFFECTS OF LOW TEMPERATURE. There is a topic above all others an Englishman can con verse on under any circumstances, irrespective of condition or creed, viz., the weather; and few avocations are influenced by atmospheric changes to the same extent as the photographer’s; yet the variable conditions have their uses, though it may be a trifle uncomfortable for those who have to work in them. At the present time we not unnaturally expect a little severe weather, when lowness of temperature is certain to give trouble in several depart ments; carbon printers, plate coaters, and workers in gelatine generally, not being among the exceptions. In the studio there is no longer any necessity for thaw ing the negative bath, encasing the collodion-pourer in warm clothing, or boiling the developer, in order toZobtain an image which, when finished, appeared to be more or less embellished with ice patterns, and the beauty of which might be considered doubtful. Those days of worry have happily departed, and we now find a necessarily increased exposure to be the only real drawback in negative making during cold weather ; even that need cause but little incon venience if development be less restrained. The extent to which restrainers may be employed for the purpose of checking over-exposure has often been pointed out in these columns; the reverse applies with equal force when short or under-exposure becomes a necessity. There is much gained, both in time and quality, by keeping the developer at a temperature of 659 p Ammonia is an exception to this rule, owing to its volatile nature ; it may be added to the heated pyro solution immediately before development commences with greater advantage. That cold slows the action of light on a bromide plate is not an unnatural conclusion to arrive at, and a similar action is familiar to all who have practised the collodion processes. The cause in its scientific aspect has, however, been conclusively shown in a series of experiments con ducted by Captain Abney, recorded on page 315 of our last volume, and need only here be referred to. Captain Abney found, upon warming a plate which registered 18° on Warnerke’s sensitometer, that the plate became more sensitive, and registered 24° when exposed under the same standard phosphorescent plate. Pursuing his experiments in the contrary direction, he found cold, induced by the application of ice, &c, slowed the sensitiveness in the same proportion as heat accelerated it, or, employing Captain Abney’s own phrase, “ Cold diminishes sensitive ness by causing the amplitude of vibration of the mole cules to be obstructed,” These experiments, of course, operate independently, in a measure, both of season and direction of air currents, each of these latter exerting an influence on plate coating and drying, negative making, and printing operations. Silver printing has not lost any of its unpleasantness in cold weather; still, judging from results obtained by the modified gelatine processes, albumen can scarcely be ex pected to carry us through many more winters; until the arrival of that panacea, the usual precautions already given in these pages must be enforced. A few points may be reiterated here for the sake of convenience. Sensitizing takes place less quickly when the temperature of the bath and apartment is below 60° F., than at or beyond that reading; therefore, the usual time of floating may be doubled at this season without any corresponding dis advantage. The temperature of the drying apartment should not be allowed to fall below 50° F., as cold tends in a great measure to loosen the sensitive coating of albu men from its support, and in the after process of washing this becomes apparent. We have frequently seen prints, the surfaces of which had become partly detached in wash ing from no other cause than allowing crystals of ice to form on the surface after withdrawal from the sensitizing solution. The use of preserved paper does away with the annoyance to some extent, but not altogether, for albu men prints exposed to a low temperature on removal from the washing apparatus, become excessively tender, and if permitted to reach freezing point, will not bear anything but the most careful handling. Toning and fixing solu tions each perform their functions in a more satisfactory manner if they are heated to 70° F., beyond which limit it is not wise to go. The water employed for washing prints before and after toning should also be of equal temperature. Hyposulphite of soda is more easily removed in water slightly heated, and those who have to perform that task find it more agreeable, hence the work is effectively performed. Speaking in general terms, equal temperatures tend to the production of equalr esults, and these exigencies are easily met by a proper system of heating. Printing indoors at this or any other season is entirely out of the question for photographers who have any reasonable quantity of work to perform. And here again “Jack Frost ” delights in obstruction by solidifying the condensed vapour on the glass surface of the printing-frame, and thereby causing uneven results; in fact, during a severe frost we have seen a perfectly opaque coating appear on the printing-frames within half-an-hour, thus causing considerable energy among the printing staff, as a large number of frames were exposed. We need hardly say that removing the frames to a warm room for a few minutes melted the coating and allowed the glass to be repolished without in any way injuring either negatives or prints,