Volltext Seite (XML)
106 THE PHOTOGRAPHIC NEWS. [FEBRUARY 13, 1885. their place well in the front, as they always have been in all things appertaining to photography. Quite recently so much has been written, said, and done in this and every other country in the world respecting this new system of positive printing, that there appears little left to say that has not already been said and commented upon. It appears pretty well decided, in the minds of most who have tried the new method, that it is the printing process of the future. Some go as far as to say that albumenized paper will be entirely super seded. I must admit we are not quite so sanguine as that, although we are quite convinced that it will, under certain con ditions and in many instances, serve the purposes of albumen ized paper, and where the latter would be unusable. We also believe it will be found useful for many other purposes beside printing from the photographic negative. There is no question of doubt that the range and variety of tones and all-round general excellence obtainable under skilful treatment are superior to anything obtainable upon albumenized paper by any modern method. We all know the vexatious, troublesome drag the printing has been during the winter months ; it was always bad enough with the old wet plate negatives, but the advent of dry plates has in creased the difficulty to such an extent that I doubt whether it has been found profitable, taking all things into consideration (loss of repute from inferior prints, &c.), to carry on printing at all in London during two or three months of winter. Every now and again the cry has been raised for a quicker printing process. Many and various suggestions have been made from time to time in the journals for years past, and at last sheer necessity, that true Mother of Invention, has again asserted her supremacy by coming to the rescue ; hence gelatino-chloride paper. There is one—as I take it—very healthy sign in connection with the introduction of this paper, and that is, it has the usual number of detractors, like all other good things that have come before. Retouching, dry plates, and many other valuable in troductions have all met the common fate of new departures. There are many advantages in the use of this paper over that of albumen, and amongst the rest I will name that of the humour ing of dense or weak negatives, varieties of tones, the facility of production, independence of daylight, and last, but by no means least, its undoubted permanency. Now with regard to the latter virtue, I have something to say. Many photographers, and some of those of eminence in the profession, appear to have some doubt as to the permanency of prints produced upon gelatinized silver paper, but on this point we are particularly sanguine. Our argentic gelatiuo paper, a similar kind of preparation to this chloride, has now been before the photographic world for some years. We have made many thousands of photographic prints, some hurriedly for experi mental purposes, but have never yet seen a single faded print; we have occasionally seen a slight jellowing, but that has always been attributed to some neglect in the manipulations. Mr. G. S. Penny, in the Year-Book for 1885, page 53, in suggesting the use of gelatino-chloride paper (before it was an nounced as a commercial article) speaks there of prints made by himself more than ten years ago, and are now as good as the day they were made. When gelatino-bromide was first talked about some sixteen years ago, we made some rough experiments on paper, but as we could not get sufficient sensitiveness, we did not go on with it; on reviewing our experiments some years since, we looked up some prints of our first trials, and, to all appearances, they were as good as the day they were made. I have submitted many prints on our paper to various severe tests, and have now in our possession prints that can be seen by any one who cares to see them, that have been exposed in a southerly aspect quite un protected from the sun’s rays for four years, and are as good as ever. This, I think, may be taken as a fair test of their un doubted permanency. ENLARGING UPON GELATINO-BROMIDE PAPER. BY J. GEDDES.* At.THOt'Gir the task before me to-night is more that of doing than of saying, I cannot help, in a few words, contrasting the gelatino- bromide process of enlarging, with that of the salted paper and gallic acid process of days gone by. The older method was a favourite occupation of mine, and many a good enlargement by * Abstract of a paper read before the Dundee and East of Scotland Photo- graphic Association. that method I had the pleasure of producing. Although never thoroughly satisfactory in themselves as finished pictures, they served well as a basis for painting upon in oils, and in my case it was entirely for that class of work they were produced. I had, however, always a certain amount of misgiving as to the stability of these enlargements, even although painted upon. The foar of fading or breaking out into big yellow spots loomed before me, coupled with the uncertainty of thoroughly washing large paper pictures ; but as the craving for portraits in oil of a cheap kind began to wax strong, something had to be done, and with tho feeling that “ familiarity breeds contempt,” fear gradually diminished, the result being, the more in quantity put out, the less the thought of stability. I here show an enlargement by the gallic acid process. It is some ten years since it was done, and you will observe that it has faded considerably—more in patches than otherwise; possibly, this was due to insufficient washing. When the Lambertype process became the rage some eight or nine years ago, I tried another method—that of making an enlarged life-size head from quarter-plate transparency, and by the single transfer process converted it into an enlargement for painting upon, believing that permanency here was assured. I now show one by this process which has been rolled up side by side with the one previously shown for some years. You will see that there is not the least apparent trace of fading, and the colour is as bright now as it was the day on which it was made ; but even although permanent, I had to give up this method as expensive and laborious, and fall back again upon the method previously spoken of. Contrasted with the new process, the whole was as difficult and troublesome to work with as the new is simple and easy. Regarding exposure, this can only be judged by noting tho density of light and quality of negative—possibly from three or four seconds to three or four minutes. But while we are using the lantern to-night as a means of enlarging, it can also be dono in daylight without the aid of a lantern at all. Make a room, or out-house, thoroughly light-tight (I have brought in a wash house with great success); remove a pane of glass—one foot square is amply sufficient—darken all the rest of window ; lay on the bottom of this openings piece of wood horizontally, and upon this wood or shelf place a quarter-plate, or other camera, with the focussing end outside the window, the lens facing your enlargement; remove focussing slide, and put in its place a carrier fitted to slip in, containing negative. Outside the dark house place a mirror on a continuation of same shelf, at an angle of 45°, to receive, and place upon, the negative a direct sky-light, or so angled as to receive the direct rays of the sun. Exclude the light round the camera by throwing round it a large focussing cloth, and you are ready for work. In my case, I block up the window with two thicknesses of yellow cloth, with a black cloth screen over all, which screen I remove partially when about to develop, and have a good and safe light to work by. In deve loping I may say that I strictly adhere to published formula. The making up of the developer, however, is a very simple matter. It consists of a saturated solution of neutral oxalate potash, saturated solution proto-sulphite iron, bromide of potas sium GO grs. to 1 oz. of water. These are called stock solutions, and are made up in separate bottles. Complete saturation is eftected in the case of tho neutral oxalate and iron by adding crystals to boiling water till no more will dissolve. To develop, take :— Neutral oxalate 3 parts Proto-sulphate iron 1 part Bromide of potassium, 1 minim to every 3 ounces The order of mixing must be strictly adhered to. Add the iron to the oxalate, and then the bromide. Alter development, which ought to be complete in three or four minutes, wash in a few changes of water, and then soak in a saturated solution of common ground alum ; well wash again, and fix for about five minutes in Hypo soda 1 part Water C parts A few hours’ washing after this will complete the operation. Tho pictures must then be dried spontaneously, and can be mounted with good starch or any of the usual mounting medium, taking care not to wet the face of the paper. WATER SUPPLY FOR THE DARK ROOM. The figure (p. 107) shows an arrangement of a very simple cha racter, devised by Mr. H. T. Anthony, for supplying water to adark room in a country house. As will be seen, it consists of a tall stand supporting a barrel for water. Over the top of the barrel