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THE PHOTOGRAPHIC NEWS. 377 photographers much ible results. less skilful has led to the most remarkal blem : by ma! drachms 0-75 0-50 0-40 Is the month of April last MM. Teisscre and Jacquemet communicated to the Photographic Society of Marseilles the Dry Collodion process they employ with so much success, and which, in the hands of amateur Ether ... Alcohol... Pyroxyline Iodide of cadmium Iodide of ammonium .. Bromide of ammonium DRY COLLODION—THE TANNIN PROCESS. BY O. DE VYLDER. We are of opinion that we cannot too much draw attention of photographers to the importance of dry processes. Wet collodion appears to have acquired the monopoly of producing portraits. But to dry collodion will belong, sooner or later, the monopoly of producing views. Now the vocation of the photographer is not to produce portraits exclusively : that in some respects is the commercial section of the art. The true mission of photography, in our opinion, essentially artistic, we might say civilizing, is the popularizing of the master-pieces of art, so that the idea of the beautiful may descend to the million, and plant the fruitful seed of the idea, of the good and the true, and the representation of scenes from nature, so that the knowledge of distant countries may be prohibited to the many, and that the majority may share the pleasures enjoyed every hour by those who travel wherever they list, with the sole obj ect of seeing, learning, and knowing. If it be true that wet collodion can, up to a certain point, suflice to the reproduction of pictures and engravings, it is indisputable that for taking views from nature, it is alto gether insufficient, or rather, much too embarrassing on account of the baggage and apparatus required to work it in the field. forthe first time undertakes the reading of the “Tannin Pro- cess" is, in some measure, intimidated by the minute details, by the precaution to be taken, the accidents to which ho is liable, and the causes of failure, of which the author is not sparing. i t demands no small stock of courage, to proceed, without deviation, to the end of this labyrinth ot details, and a certain amount of perspicacity to separate what constitutes the essence of the process, from the material conditions by which to accomplish its execution. To cause this process to be adopted and become popular, only its peculiar charac teristics should be given, and the leading features of its manipulations, and leave to experience the care of regu lating the precautions of detail. GO drachms. 40 1 drachm However ingenious and complete the portable laboratories invented may be, the necessity for developing on the spot immediately, the employment more or less simplified of developers, intensifiers, and fixing agents—will always prove serious obstacles to these apparatus becoming popular and generally adopted—which is also a matter of regret. Let us, however, hasten to admit, so as not to offend the exclusive partizans of wet collodion, that this necessity for obtaining the first negative upon the spot, is sometimes an advantage in this sense, that if the negative has not the requisite qualities for giving good positives, enlarged or not, we can obtain another immediately without difficulty. But this advantage over the dry Iprocess will no longer exist from the time that the latter becomes sufficiently certain, and perfect to furnish at once, a picture in the desired condition. It is from this point of view especially, that we call the attention of photographers to dry processes. He who succeeds in supplying a dry collodion more sensi tive than any known at present, which will simplify mani pulations without compromising the final result, will render a real service to the art. In this respect, Major Russell has nearly solved the pro blem : by making Known the properties of the preservative coating of tannin, he has, in great measure, caused the great difficulties of the albumen process to disappear, ho has also simplified the process, and made an immense step in advance in the taking of photographic views. But it must be admitted that in the pamphlet in which Major Russell describes his process, the explanations he gives are not calculated to encourage experiments. He who very popular. It is very simple in its working; and tho bulk is reduced to the smallest compass, it presents therefore all the advantages we look for in an apparatus with which we have to traverse plains, or climb mountains. It may be objected that the negatives it yields are too small 34 inches by 4 inches. But these are the dimensions of stereoscopic pictures so very popular at the present day, and if they can afterwards be enlarged by a process as simple and ingenious as that indicated by M. Testelin, in a pamphlet he pub lished some years ago, it will be possible for any one pos sessing a whole plate apparatus to obtain with the greatest facility positives or negatives enlarged from the negative furnished by the autopolygraph. We now arrive at the explanation of MM. Teissere and Jacquemet’s process, which although, it ‘differs but slightly from that of Major Russell, deserves, nevertheless, to be regarded as a special process. 1. Collodion. Every collodion which yields good results in the wet process may be employed in this. Remarking that it must contain at least 1 per cent of iodide and l-3rd of bromide. We generally make use of the collodion described by M. Van Monckhoven in the last edition of his “ Traite de Photographie," lightly increasing however, the quantity of iodides and bromides. The following is the formula of this collodion:—■ These remarks of course apply only to the form given to the pamplet, and not to the process itself, for which we have perfect sympathy. We only think, contrary to the opinion of M. Girard, that in the explanation of the pro cess, useless details are sometimes misplaced ; those to whom photographic treatises are already familiar, more or less, very well know the infinite precaution which must be taken at every moment, and moreover that a failure in this, as in all other things, teaches more than any amount of written expla nation. We repeat that in rendering sincere homage to the . valuable discovery of Major Russell, and in acknowledging the services it is called to render, we admit that there is a necessity for explaining it in the clearest manner, and in tho most inviting also. It is with this object in view that we have solicited and obtained permission to give in our course of instruction at the School of Industry, and to publish in the Bulletin Beige de la Photographic, the tannin process which M. Jacquemet has wished us to communicate the explanation is ; given with such simplicity and clearness as to dispel from the first all idea of failure. Candidly, wo cannot too much exhort amateurs to try this process ; we are convinced that they will succeed at the first trial. In our experiments we have employed the autopolygraph invented by M. Vidal, an apparatus less known than it deserves to be, but which is undoubtedly destined to become MM. Jacquemet and Teissere have undertaken a series of experiments concerning the employment of a special collo dion, more sensitive than ordinary collodion. But as these experiments are not yet completed, and as it is also but just that to the inventors alone should belong the honour of initiating the public, we abstain from mentioning even the principle upon which these experiments are based? The plates are not gelatined. This is a step in advance, for the application of gelatine is a delicate and difficult operation. Ihe collodion is therefore directly applied upon a well- cleaned plate ; taking care to leave no corners. To cover the plate easily, we hold the plate with a tuft of cotton slightly moistened with distilled water.