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  The research archive of Gary W. Ewer regarding the history of the daguerreotype

On this day (May 15) in the year 1891, the following article appeared as the fourth in a series in "The Photographic Times" (New York; pp. 183- 5): - - - - - - - - - - - - - - THE RISE AND FALL OF THE DAGUERREOTYPE. AS SEEN BY A COUNTRY "OPERATOR." IV. The mercury bath consisted of an iron vessel in form of a hopper, a little larger at the top than the largest plate, and a little deeper than the length. A rod from the side of this to the side of a circular base supported it directly over the latter, on which stood a small spirit lamp with a flame-regulating tube. The bottom of the vessel was formed into a small cup in which was placed about an ounce of pure mercury, which was frequently filtered through a cone of clean paper perforated at the apex with a needle, through which fine aperture the liquid metal ran, leaving dust and dross behind. The cup containing this was kept about blood-warm by a tiny flame during working hours, but when a plate had been exposed in the camera the plate holder was taken to the mercury bath and placed, face down, over the top, the slide drawn and the flame of the lamp increased a little. This was usually done in what was then called the dark room, but the light needed only to be weak; the plate could be safely developed in a place distant from a window and but little screened from the light. A thermometer was furnished with the mercury bath, but was almost always broken in a short time, and of course but little used, the hand being a handier and quite as reliable a test. The temperature was raised, not too rapidly, to about 150 deg. Fahr. The operator soon learned to judge by the sense of touch when the vessel was hot enough, and could then light a match, and raising the plate a little, see whether it was fully developed or not. The operation was very simple and admitted of little variation--not even as much as the development of a wet plate. It did not appear to consist in the reduction of the silver from the haloid impressed with the light as in the modern dry plate, and was certainly unlike the manner in which the image is formed on the wet plate, which chiefly consists of silver derived from the free nitrate and deposited on the foundation traced by the actinic rays. The silver plate, covered with a coating of iodo- bromide of silver and not exposed to the light, was impervious to the vapor of the mercury, but after it had been impressed with the image of the camera, the molecules of the sensitive coating were so changed as to allow the evaporated mercurial atoms to pass between them to the plate beneath in obedience to the affinity of the two metals for each other. When we think of it, all this is wonderful. We are led to ask, How does the image in the camera affect this coating so that without any visible change it does open its doors to the rising particles which otherwise would knock in vain for admittance? Where the light was too strong, as from a broad white shirt front, for instance the image was often lost by solarization; that is, so much mercury united with the silver in that space as to produce a flat dead blank without detail. This defect was sometimes remedied by using a false front of light nankeen. The plate, after being taken from over the mercury, could be shown to the sitter, much as a chemical proof can now be shown, but with much greater precaution, lest it should be marred in the slightest degree. If not satisfactory it was set aside to be rescoured and repolished, and a new plate taken for another sitting. It was customary to have on hand a supply of plates ready for the last short buffing which it was necessary to give them the last thing before coating, not only to remove any dust but also any effect the atmosphere may have produced upon them while waiting to be used. If portraits were to be taken the last buffing was across and not lengthwise of the face. When the likeness was found to be worthy of approval, it was fixed by immersing it in a solution of hypo, and it was quite as readily seen when the fixing was completed as it is when that of a negative is done. It was then washed with clean water, when it was ready for gilding. The gilding solution was made as follows: Fifteen grains of chloride of gold were dissolved in 16 fluid ounces of pure water. In an equal quantity of water 55 grains of hyposulphite of sodium were dissolved, and to this was added, a little at a time, with frequent stirring, the gold solution. The whole became colorless in a short time. The edges of the plate having been bent up before fixing, it was held at one corner by a pair of pliers in a horizontal position and covered (while wet from the washing) with the gilding solution which was then uniformly heated by passing underneath it the flame of a spirit lamp. Small bubbles caused by the heat soon covered the surface of the plate and the tone of the picture visibly improved, the high lights became more brilliant, the shadows deeper. As soon as the bubbles disappeared the heat was withdrawn. After waiting a moment the solution was thrown off and the plate thoroughly washed and then dried over the lamp. Then, as now, the most beautiful result was not quite satisfactory. But there was one great advantage possessed by the daguerreotype: the wrinkles and characteristic lines could not be obliterated by the retoucher's pencil. The mouth could not be shortened, the hollows of the checks filled up; the nose reduced, eyebrows retrenched, the old face made to look young, nor in fact any of the abominable defacements and falsifyings practiced, which are now so common, and which I cannot help thinking have much to do with cheapening and demoralizing the art of photography. A perfect daguerreotype needed no artificial aid to its beauty, but it was customary, and usually required, to give a little color to the lips and cheeks as well as to touch the rings and other jewelry with gold, which, though not strictly in good taste, was quite harmless, as it could be easily removed at any time if so desired. Probably no picture ever made was more lasting than this, when properly finished. I have many which have been made more than forty years that are as bright and perfect as when first made. But they cannot be long kept exposed to the action of the air, this being charged with impurities by which the surface of the plates are susceptible of discoloration. It was therefore necessary to protect them; and for this purpose a supply of white plate glass cut to the exact sizes of the silver plates used was kept on hand, with corresponding mats, preservers and cases. To put up the finished picture the mat and glass were placed over it and the three bound together with strong adhesive paper which secured the edges and lapped over on to the back. This was followed with the metallic preserver, which framed the glass in front with a neat border and was wide enough to bend down also on the back and so form a protection to the sealing paper. Finally, all was pressed into the case, when the work was ready for delivery. Experience has proved several interesting facts in relation to daguerreotypes. One of these is, that neither light nor age appears to have any injurious effect upon them. I have some very old ones that were hung outdoors on the south side of a building for years, and which are still in a perfect state of preservation, apparently unchanged. It is a curious fact that most of these in my possession which were put up in contact with brass mats have become much discolored under the mats, the discoloration spreading inwards upon the picture to a greater or less distance. Some with paper mats have been similarly affected, while others have escaped. The inference from all my observations has been that if protected from dampness and the sulphurous gases which pervade the atmosphere, a properly finished picture of this kind is imperishable. Those that have lasted forty or fifty years unchanged are, or seem to be, in themselves reasonable proofs that they may last a thousand. Even those which have become much tarnished may be quickly restored to their original brilliancy by immersing them in a hot solution of cyanide of potassium, a treatment heroic enough to speedily wipe out almost any other species of the photographer's art. If any should wish to restore an old daguerreotype by this process, he should clean off all the paper from the back, and be careful to use cyanide that is not partly decomposed, as shown by an ammoniacal smell (good commercial cyanide which is dry and solid is suitable); above all it must not have been used for fixing, lest the picture by spoiled by scum of silver deposited from the solution. Dissolve about half an ounce of cyanide in a pint of water, and heat in a porcelain evaporating dish. Immerse the plate, face up, move the dish, continuing the heat until the color disappears, then remove the plate and wash it thoroughly under the tap. It can be dried by leaning it cornerwise and nearly upright in the top of a graduate, or in the old way by holding it at the corner with a pair of pliers, and heating it from the top downwards. W. H Sherman. (To be continued.) (Previous installments appeared on Jan 20, March 13, and April 17 and were posted to DagNews in 1997 on the date of their original publication. The fifth installment will appear on September 4.) -------------------------------------------------------------- 05-15-97

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