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THE PHOTOGRAPHIC NEWS. LMAY 1, 1885. recommendation, apart from all else, of being true both to form, and in perspective, which could seldom be said of the work of the wood engraver at a period anterior to the use of the camera. Many of these photo-mechanical processes are very beautiful, especially the Woodbury type, and have exercised a beneficial influence on the work of the engiaver; much even of the wood cut portrait work of the present day, apart from the tool lines of the workman, having, as regards light and shade, all the cha racteristics of the best photographs. With respect to mural pictures, such as are constantly to be seen in populous districts on the immense posters, and now so extensively used as advertisements by theatrical companies, it does not require much discrimination to trace the indebtedness of those who produce them to the art of photography. Some of them are indeed charming, in fact quite works of art in their way, and at no period in the history of the art of printing have pictorial posters of such high merit been produced, as those of the present time. This is saying a good deal, but not a whit too much either for those whose untiring genius has developed this branch of art industry to its present state of marvellous excellence, or for the influence which photography has so clearly exercised in directing that industry to its present perfection. It is further pleasing to note that although in the early history of the art-science, artists were wont to fight shy of the photographer, and to look upon their productions as being of a too mechanical nature to be worthy their notice, that state of things is now very much altered, and I have of late years come in contact with many eminent painters who have freely admitted the assistance they have derived in working up the details of their pictures from the study of photographic prints. Of course the true artist will always go directly to nature for her colours and her evanescent effects, but for form and detail he will never go far wrong in relying on the fidelity of a photograph. Correspondente. POSITIVES ON GELATINO-CHLORIDE OF SILVER. Dear Sir,—Will you kindly afford us an opportunity to make a slight, yet important, correction to our formul, which appeared in your issue, April 17th. Page 245, first column, 28th line, should be, ammonium chloride 124 grammes, instead of 124 grammes ; and tbe following line should be, potassium chloride -88 grammes, instead of 88 grammes.—Yours faithfully, Ashman and OrFORD. A PHOTOGRAPHIC CLUB FOR AMATEURS. Sn:,—Amateur photography, I find, has worked its way even amongst the Eton boys, so universally have its delightful fascinations spread. It has occurred to me that the time has come for amateurs to have a club of their own. If those of your many readers who feel the need of a place in London where amateurs can meet and hold interchange of ideas upon this most interesting and profit able pursuit will lend me their support, I will proceed at once to form a “ Camera Club ” for their immediate benefit. I will thank those who write to me direct upon the subject to put on the outside of the envelope the words “ Camera Club,” so that the correspondence receive the special attention it deserves.—I am, yours truly, Cumming Macdona. April 29th, 11 ilbre House, West Kirby, Cheshire. o — Proceedings of Sotieties. Photographic Society OF Great Britain. A technical meeting was held on Tuesday last, the 28th nit., in the small room attached to the Gallery, 5a, Pall Mall Fast, Mr. W. Bedford in the chair. Mr. A. Cowan exhibited his combined camera and changing box, a description of which appeared on p. 238 (ante). A point not previously mentioned was the automatic registration of ex posed plates. This was achieved by the rotation of a serrated wheel in connection with a dial plate, the same being revolved one section upon each change of plate. The Chairman characterized the exhibit as wonderfully in genious, and he thought that although Mr. Cowan gave much of the credit to Mr. Harrison, yet the camera before them showed several improvements introduced by the exhibitor. Such cameras would doubtless come more into use when they succeeded in getting developed prints uniform. Mr. W. Cobb said he had some experience with the working of Mr. Harrison’s small camera, and found no difficulty with it; still, he was not prepared to say that he would prefer taking small plates for subsequent enlargements when there was an opportunity of making the negatives direct. Mr. W. Brooks had often made 10 by 12 negatives from 2 by 2 negatives, and they were quite satisfactory. The following question was then read and discussed:—“ What are the Chemical Reactions which take place on the addition of Alum or Tannin to Gelatine, and what is the Difference between the two Precipitates so produced ; if any ? ” Mr. A. SILLER thought the chemical effect produced by tannin on gelatine was not well understood. In the case of‘alum he considered it would be decomposed, the alumina then com bining with the gelatine to form a compound of these two sub stances. Chrome alum would also act in a somewhat similar manner. Mr. Atkinson understood that a certain decomposition took place at the parts in contact, but not through the whole mass. If he put a plate in dilute sulphuric acid to remove stains, it did not frill; but if he soaked the film some time in water after wards, it floated off the plate. This led to a discussion on the removal of yellow pyro stains from negatives. Mr. Brooks supported the claims of dilute 1—80 sulphuric acid, inasmuch as the colour did not return after continued washing, as it does with hydrochloric and other acids. Mr. Cowan preferred the alum bath before fixing. The Chairman obtained black films by adding four ounces of ferrous sulphate to each sixty ounces of fixing bath, taking the precaution to keep the bath neutral. Another question was then read as follows:—“ What are the chemical and physical properties of the compound produced by oxidizing gelatine with bichromate of potash, and light ? ” Mr. A. SPIILER instanced the usually accepted theory of carbon printing ; he did not think that gelatine became oxidized, however. There being no further remarks on this question, Mr. Atkinson passed round three plates to illustrate reversed images by increasing exposure. Mr. Cowan referred to an experiment wherein he obtained positive and negative images on a test plate under the sensi tometer. Mr. J. D. England had obtained a similar result. Mr. Dagley sent a cabinet for washing plates; it was filled with a series of zinc trays placed on shelves for the purpose of economising the water, which passed from one to the other, through the series, the upper tray receiving the supply. Several speakers advocated washing gelatine plates by placing the film downwards. Mr. Pringle had several boxes, each made to wash six plates with the films downward, and he had no trouble with stains afterwards. Mr. J. D. England enquired if eosine had been found so far to be the best substance for staining gelatine plates? Mr. A. Spiller : According to Dr. Vogel, azaline is preferable, since it has a more decided effect on red tints than eosine. Mr. Gale enquired the best means to remove red stains from old gelatine plates which had been apparently imperfectly fixed ? The general opinion of those present was that if neither acid nor potassium cyanide effected removal, the case was hopeless. The Chairman strongly advocated the use of a thick coating of collodion to negatives before printing, not merely pouring on and off similar to coating plates, but allowing it to set on a levelling stand. Negatives protected in this manner had with stood the action of blotting-paper moistened with silver nitrate for the space of twenty-four hours. It was announced that in future the rooms will be opened on Technical evenings at 7.15, to enable members and their friends to peruse the home and foreign photographic literature before the business of the evening commences.
