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714 THE PHOTOGRAPHIC NEWS. | October 16, 1891. first photograph of a living buffalo which had ever been made. With the new lens, pictures of wild animals will be possible without going near enough to scare them away, and, perhaps we should add, without the risk of being scared by models who would certainly decline to “look pleasant.” The naturalist will also find in this new photographic lens a means of recording the habits and movements of many creatures whose natural timidity forbids a near approach to their haunts. We alluded last week to the great value which such an instrument would have in military operations, and now that it is demonstrated that distant images of large size can be secured with short exposures, there is no reason why the navy should not participate in its use. Pictures of passing ships and snap-shots at distant shores may often prove of value in strange waters, while those who delight in taking photographs of “white wings ” need not go to sea for the purpose, but can fire away at them comfortably from the shore. It need hardly be said that, like the telescope, the field of the instrument is a restricted one, but this will by no means diminish its usefulness. It will probably supplant the telescope to a great extent among amateur users of that instrument ; for it will be possible to see the images of objects on a screen, while, at the same time, those images may be made permanent. There is also some hope that the lens will help in the construction of a real “ detective ” camera. What we mean is that suspicious individuals can be photographed without any near approach to their persons, and from the cover of a house. We shall look forward to the promised publication of the means which Mr. Dall- meyer has adopted in the construction of this lens, which we think bids fair to be the most important contribution to the optical side of photography which has been presented for some time. ON THE INTENSIFICATION AND REDUCTION OF GELATINE NEGATIVES* BY ROLAND WHITING. I suppose that every photographer has at some time or other found it necessary to reduce or intensify his nega tives, so as to make them printable ; or, at any rate, so as to cause them to yield better prints, and the best means of bringing about the desired result in the best possible manner has, no doubt, been a matter of difficulty. And necessarily so, for intensifying and reducing, even in the most experienced hands, are far from being certain pro cesses. They require a considerable amount of care and watchfulness to make them result as they should do, and even then there may be effects brought about which are different to what were intended. As a rule, these processes are looked upon as nuisances, especially amongst pro fessionals who have not much time to devote to them, and consequently the negatives requiring such treatment are put by until some time when they can be conveniently attended to. As soon as a lull in the general rush of business occurs, they are hurriedly despatched. In the case of mercury intensifying, the negative is first plunged into water for a few minutes, and then into a * Real before the North Middlesex Photographic Society. solution of mercuric chloride, without having any regard to the perfect elimination of hypo. When the surface looks sufficiently white, the negative is slightly washed in water, and then immersed in a solution of ammonia until it is blackened all over; then, after a few moments’ washing, it is stood up to dry. The result of such treatment most frequently is a yellow stain which nothing will remove, and so a negative is spoilt which might otherwise have been made to yield a good print. If success is to be obtained in these processes, it is only to be got by care and attention; haste is fatal to it. I do not wish to imply that all are guilty of such neglect, but there is nevertheless a great deal of carelessness and trusting to chance with many who should know better. It is to these I most especially address the remarks con tained in this paper. I do not presume to be able to teach anything that is new or original, neither shall I introduce any formula to notice other than those that have appeared in the various photographic papers from time to time. I shall simply call to notice what is most required of an intensifieror reducer, and how far we can get it. I say how far we can get it; I ought rather to have said how little we can get it, for it is remarkable in these processes, as in most photographic things, we generally require a great deal more than we are ever likely to get; therefore, it is wise not to expect too much. Yet, nevertheless, this desire for the unattainable is by no means to be condemned, for it frequently causes us to stretch forth an effort which we should not otherwise do. Every photographer, professional or amateur, should thoroughly understand the ins and outs of intensifying and reducing, as by their aid he has at his hand a means whereby he can give additional merit to his pictures, and can often save a negative which might otherwise be lost. For instance, where a plate has been over-exposed, it is very frequently a good plan to develop it until the detail is out, stopping development before it begins to fog, and making up its want of density by intensification. A better result is often obtained by so doing, if skilfully done, than if development had been continued in the usual way. Sometimes, however, you have not the chance to stop development before the plate begins to fog, and so, you will say, such a treatment is then impossible ; but even here I have before now grappled with the difficulty by first reducing the negative with ozone bleach, which re duces the thickness of the film, and then intensifying it again with mercury, the result being a more brilliant negative, owing to the fact that the chief of the half-tone or the fog lies on the surface of the film, whereas the denser parts penetrate to a greater depth ; the bleach taking off the upper surface of the film and the half-tone upon it, leaves the darker portions to be strengthened by the intensifier. Another plan of mine has been to varnish the negative all over except where the strong parts have been, as in the case of interiors, and then to reduce the dense portions with some suitable reducer so as to neutralise the contrast. This can be very effectually brought about where a window is too dense and the surroundings are in deep shadow. The varnish is applied very carefully with a brush, and the reduction effected with potash-ferricyanide. By this method I have even gone so far as to take out the back ground from a portrait negative, leaving the head upon a clear glass ; but it requires very carefully doing. Now, before we go on to formula), it is best that wo