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THE PHOTOGRAPHIC NEWS. Vol. VII. No. 240.—April 10, 1863. CONTENTS. PAGE Ammonia Fumes in Printing 169 Photographs in Printing Ink •• 109 How to Print-in Skies from Separate Negatives. By Wm. L. 170 Report on the New Fixing and Developing Agents ••••• 17 On the Most Recent Spectrum Discoveries. By Professor W. Allen Miller, 173 A Short Lesson in Photography.—No. 12 -73 PAGE Photography and Bad Taste 174 Photographic Piracy of Engravings 175 Proceedings of Societies.—London Photographic Society.—The American Photographical Society 176 Correspondence.—Foreign Science, 178 To Correspondents ISO Photographs Registered during the past Week ISO . AMMONIA FUMES IN PRINTING. T’IERE are some singular discrepancies of experience in con nection with this process which require clearing up before it can become of practical benefit to photographers. Our readers have already had some record of failures in connection with it; but, with a promised improvement in the production of photographic prints, we are unwilling to allow a few failures to stand in the way, or condemn the plan as entirely useless. At present the experience is singularly conflicting, and we wait for further and more definite information before we can arrive at a decision on the question. In our last, we gave a communication from Mr. Penny, of Cheltenham, in which he detailed his experiences, which were very strongly in favour of the fuming. Its effect, as illustrated in the specimens we received, appeared to be a great increase in sensitiveness, and a greater- richness and depth of tone; the same treatment in toning giving decidedly greater depth. This experience coincides with that of various American authorities who have given opinions in favour of the process. The experience of some other operators, however, is not only opposite, but is very anomalous and varied. Mr. Debenham, who stated the results of some expe riments at the Photographic Society last month, found, absolutely, no difference in the final result between the paper which had been fumed, and that which had received no such treatment. Mr. Hughes, in detailing to us the results of his own experience, described the fumed paper as assuming a greyish-blue tint in the pressure frame, and retaining that colour, more or less, whilst toning, fixing, &c., and after it was finished ; the print being neither so warm or so vigorous as others from the same negative printed and toned in the usual way. We have recently been trying some experiments ourselves, and we meet with results, in many respects, decidedly the opposite to these; but still, in our estimation, a failure. We will detail exactly our operations. We used Saxe paper, highly albumenized, and salted with seven grains of ammonium and one of sodium to the ounce, and which, by the ordinary treatment, gave us very good results. This was excited on a bath originally neutral and sixty grains to the ounce, but reduced by working to a little under fifty grains ; having just been decolourized with a little chloride of sodium a slight trace of nitric acid was set free. Sheets of paper excited on this bath were divided, one half fumed, and the other left as it was. The fumed half and the other half were printed together on halves of the same stereoscopic negative, "he fuming was effected by placing a saucer containing a little of the strongest liquor ammonia in a box, to the lid of which the sensitive paper was pinned. The first floating of seven minutes slightly attacked and disintegrated the albu men. Subsequent fumings of the same duration and of about five minutes did not show any such result. The effect in printing was altogether different to what, from the expe- i lence of others, we had been led to anticipate. In the first experiment the fumed paper required an exposure of about one-fourth longer than that which had not been fumed. It printed much redder, and with more contrast or brilliancy, and these characteristics continued throughout subsequent operations. When toned in the same acetate and gold bath, it coloured a little more slowly, and remaining in the bath for the same time, as also in the fixing bath, final washings, the finished print is redder, lighter, and possesses a little more contrast than the other half which had not been fumed. Other experiments were similar ; in some cases the amount of sensitiveness seemed equal between the fumed and the unfumed paper; but in all cases the tone was redder in the pressure frame, and continued so to the end of the chapter. In some cases there was a little more contrast in the fumed specimens, but in no case either greater sensitiveness or depth of tone. We must confess that however promising some of the results may have appeared, we fear there is too much un certainty in the very nature of the process to give promise of much practical value. In fuming we have no means what ever of arriving at certain or uniform results. Whatever the action of the ammonia may be, we have no means with such a process of fixing the exact extent of the action or the amount of the combination. Even if the same time be given to each sheet, the result must vary for the strength of the ammonia is constantly changing by the evaporation. The presence of ammonia fumes in any part of a photographic establishment, is moreover scarcely desirable. If the good were certain and definite, this might doubtless be got over; but we fear that until the conditions of success are more accurately defined, tempting as the promise of perfect prints may be, the fuming process will not prove of much practical value to photographers. PHOTOGRAPHS IN PRINTING INK. We have recently been favoured by a visit from Mr. Pouncy, when he showed us some specimens and made some ex planations which give a more specific meaning to the term “ photographs in printing ink ” than it has seemed to possess in a recent correspondence which has appeared in the Times and some portions of the photographic press. By the use of this term Mr. Pouncy does not simply mean prints from blocks obtained by the art of photography, as in Herr Pietsch’s productions, nor photolithographs or photozincographs, nor even the photographic transfer pro duced in printing or other greasy ink ; but positive prints produced, direct from the negative in the compound of carbon, oils, and varnish, known as printing ink. The mode is the subject of a patent, the specification of which will not be published for a few months. We are at liberty to say, however, thus much of the method of opera tion. A suitable photographic paper is covered by means of a brush with a preparation of printing ink containing a salt sensitive to light, and affected in the same way as the bichromates. This is ready for exposure under a negative in a quarter of an hour, or it may be kept without deteriora-