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May 15, 1885.J THE PHOTOGRAPHIC NEWS. 317 thing left behind which will not dissolve away ; he had not, how ever, touched on the theory of development in this paper, as that was reserved for a future occasion. The experiment mentioned by Mr. Spiller he intended to repeat. The Chairman then called for a vote of thanks to Captain Abney for the interesting experiments included in the paper. This having been accorded, Mr. J. WERGE was called upon to read a paper, “On the After-Treatment of Negatives.” Owing to the lateness of the hour, Mr. Werge preferred offering a few remarks on the subject, his chief object being to eluci date further discussion on Mr. Bird’s recent paper, as well as to show what could be done by a careful after-treatment of the nega tive without recourse to eosine and other compounds for a like purpose. Negatives not retouched, and others of the same sub ject carefully and skilfully worked, together with prints from the same, were handed round, likewise an example of working pic torial effects into figure subject negatives with plain backgrounds. Regarding the translation of colour by photography, he did not think much more could be done than at present by chemical means, but he rather relied on mechanical manipulation. Heraldic engravers worked to rule; mezzotint engravers were guided by a series of tints. This was illustrated by a chart containing a number of colours placed in the order of their luminosity, forming such a scale as an engraver would use. Mr. Werge was of opinion that it was only by some means of after- treatment that photographers could get a true translation of colour. He approved of the suggestion to illuminate with com plementary colours, and showed an excellent photograph from a gorgeously-coloured print which had been partially treated in that manner. Summarising, he said photography could never reach the perfection and beauty of line engraving ; the most that could be hoped for would be an approach to good mezzotint; until that is done nearly all reproductions of colour by photographing would be unsaleable. He did not think eosine helped very much ; even if it did, the result would be much the same as the print shown. The Chairman said the pertinent question put by the last speaker to Mr. Bird as to his having seen the negatives produced by Braun and Co., seemed still more pertinent after an examina tion of the negatives which had been passed round. Mr. Debenham referred to the excellent results obtained by Ives, of Philadelphia, Hrs. Vogel, Eder, and others, wherein they had been assisted by the use of certain substances in the film ; dodging negatives was occasionally advantageous, but if good results could be obtained without resorting to mechanical skill so much the better. The idea of illuminating with a complementary colour would be out of the question when a large number of colours had to be included ; practically, only the blue and violet needed diminishing, and pale yellow glass would do that. One of Mr. Werge's examples, which had been stumped at the back might be considered brighter by some, but the flesh looked to him as though it had been blown out, Mr. J. R. SAWYER was about to address the meeting, but at the request of the Chairman he agreed to re-open the subject at the June meeting. The Chaibman agreed with Mr. Debenham that it would be better to obtain good results by chemical means. He was glad Mr. Sawyer was not about to condense his remarks, as the door of enquiry was now opened and they were anxious not to lose anyone’s experience ; moreover, it would be satisfactory to have the negatives before the meeting so that they could judge how much retouching had been done. They all did a little, he thought. It was then announced that the next technical meeting will be held on the 26th inst., and the next ordinary on June 9th, after which the meeting adjourned. South London Photographic Society. The ordinary meeting of this Society was held on Thursday, the 7th inst., at the House of the Society of Arts, John Street, Adelphi, W.C., Mr. T. Bolas (Vice-president), in the chair. The minutes of the previous meeting having been read and confirmed, Messrs. G. M. Satchfield and Alfred Warner were elected members of the Society. It was announced that the subjects for competition at the June meeting would be: “ I See You,” and “An Interior.” The prints sent in for the May competition were then passed round, and the votes of members taken thereon. It was subse quently announced by the chairman that Mr. J. A. C. Branfield had been successful with both subjects—“A Newspaper Boy,’’ and “A Country Lane.” Mr. C. Hussey, Junr., then exhibited and explained “Sar geant’s instantaneous shutter and automatic exposing appa ratus.” He considered that a shutter, to be useful, should possess the four following advantages : Portability, certainty of action, simplicity, and must be completely under control; all these characteristics he had not previously seen fulfilled in any other form of shutter. An instantaneous exposure could be given, or by adjusting a screw the exposure could be prolonged to several minutes. It could be made to work in the diaphragm slot, between the lenses, or on the hood. It was actuated pneumatically, and in the case of slow exposure, the aperture would remain open so long as pressure was exerted. He thought it especially useful for the studio, as it enabled an exposure to be made without the sitter being actually aware of it. The Chairman remarked that the principle was by no means new in its application to shutters. Mr. Cowan had shown a similar action at the Photographic Club about two years ago.* In that case the drop was made of wood, and was lifted by a pin working round a slot as in the models now shown. He must say that the models which had just been exhibited were extremely well made. It was an advantage to be able to expose from between the lenses, and they would agree that it was the most compact exposing arrangement that had been shown there. The Chairman having thanked Mr. Hussey for bringing the subject before the meeting, invited remarks on shutters generally. Mr. F. A. Bridge said the principal difficulty attending all pneumatically worked shutters was leakage in the tube or bellows, which caused them to fail when prolonged exposures were required. The Chairman replied that there need bo no difficulty in stopping any leakage at the joints. In response to the Chairman, Mr. W. M. Ashman said he used an electrical exposing arrangement inside the camera, which took up very little room, not much more than the diameter of the lens employed. He gave a description, and promised to show it at a future meeting. The following questions wore then read“ Is it desirable to form a central photographic society as recently proposed?” “ When a plate is developed is the amount of reduction in exact proportion to the amount of light which has acted upon the plate?” In reference to the first question a letter was read inviting the Society to appoint one or more delegates to discuss the matter, if the members were in favour of the scheme. The Chairman explained the nature, and proposed functions of the scheme which required all the existing photographic societies to become contributors. A paid secretary would be appointed whose duty among other things would be to watch over photographic interest in bills before Parliament, such as the Poisons Act, Copyright, &c., Preservation of Commons, cheap railway fares, and the general interests of photographers throughout the country. He thought that the credit of the scheme was due to Mr. G. Smith, and he thought it a pity that gentleman was not present to expound his own views on the subject. The question was now before the meeting, “ Is it desirable to form a greatcentral society for the purposes named ? ” Mr. C. PorRSON . Cheap railway fares are desirable. Mr. W. M. Ayres could not see that a central society was likely to be useful. After a few desultory remarks, the proposition was put to the meeting and lost. The second question was then discussed. The Chairman said if reduction was strictly proportionate to ths amount of light falling upon the plate, then with the excess of light they would never get in parts so-called reversed action. Mr. C. PoiRSON : Suppose there has been only just enough exposure, would there be a point reached when all action ceased with the developer ? Mr. Poirson then enquired if there would be any reduction if bromide of silver had not been acted upon by light. The Chairman replied that AgBr, in the presence of gelatine, would be very slowly reduced, except when light has acted upon it. If the gelatine was not present, it would be acted upon quickly by the developer. Gelatine did not exert a proportion ate restiaining influence on an exposed plate. Mr. E. Clifton mentioned that he left an under-exposed • Piroroonarinc NEws, 1883, p. 305.
