Towler, John. The Silver Sunbeam. Joseph H. Ladd, New York: 1864. Electronic edition prepared from facsimile edition of Morgan and Morgan, Inc., Hastings-on-Hudson, New York. Second printing, Feb. 1974. ISBN 871000-005-9

Chapter VI.
SPECIALTIES CONTINUED.--DARK-ROOM.

THE chamber intended for all operations of sensitizing, commonly called the Dark-Room, ought to lie contiguous to and open into the common operating or work-room of the photographer; and both these rooms ought to open directly into the glass-house. As before recommended, they can be constructed on the northern aspect of the gallery, each being seven and a half feet wide-that is, half the width of the glass-room-and about ten or twelve feet long. The work-room may be that on the left, whilst the remaining chamber is on the right, with a door in the middle of the partition between them. A single pane of orange-yellow colored glass on the northern end is all that is needed; this window may be about four feet from the ground, in order that, when the operator is standing, the light whilst developing may come from below and through the negative. This mode of admitting light permits the progress of development to be distinctly watched much more effectively than by reflected light. The elevation of the pane of glass above the floor must be regulated in accordance with the stature of the operator and his habits of standing or bending during the process, so that sometimes an elevation of two or three feet above the floor of the room will be found sufficient. The size of the pane will be adequately large, if its sides are eight inches by six, and a dark-colored curtain is adjusted over this, so as to render the room almost dark in case of need. On the north, east, and south sides a shelf is constructed twelve inches wide, and three feet from the floor. In the north-west corner the pail or barrel is placed to contain water for washing the negatives; this pail or barrel is supplied with a brass stop-cock, such as is used for beer or wine; beneath the stop-cock, and on the floor, is placed the large wash-tub or sink for containing or carrying off the refuse dirty water. Beneath the north-west anal the north-east corner there will be found abundance of space for the gutta-percha developing and fixing dishes, as also for the respective solutions used in these processes, and for intensifying, as, for instance, protosulphate of iron, pyrogallic acid, cyanide of potassium, hyposulphite of soda, solution of iodine in iodide of potassium, tincture of iodine, nitrate of silver, bichloride of mercury, and sulphide of potassium. Each of these solutions must be legibly labeled, always placed in the same position, and always carefully corked. As regards the solution of the sulphide of potassium, the necessity for accurate closing of the bottle which contains it is absolute, because the fumes of hydrosulphuric acid, if allowed to escape into the room, would decompose the sensitizing-bath, and injure the prints and negatives. As soon as a negative or positive is complete, the developing and fixing solutions are poured back into their respective vials. Care must be taken here also not to interchange dishes; for the cyanide of potassium decomposes the iron-salt into what soon becomes Prussian blue by oxidation of the iron, and thus renders it a difficult task to clean the dish afterward. The first things in order on the eastern shelf are the plate-holders, leaning in their respective places against the wall; after this comes the sensitizing-bath, on an inclined frame fixed upon the shelf. The inclination may be about fifteen degrees from the perpendicular; if it were more than this, the light particles of the undissolved iodide of silver, and of other insoluble substances, would be apt to settle upon the tender surface of the collodion, and give rise to apertures in the negative. To avoid this calamity of photographers, it is preferable to have some arrangement by which the collodionized plate can be introduced into the sensitizing-bath with its collodion surface downward. For this purpose flat dishes are used with a glass or porcelain ledge on the right side to support one end of the plate, whilst the other end rests on the bottom of the dish on the left side. In this way the left end of the collodionized plate is introduced first into the bath, whilst the right end is gradually and quickly lowered, by means of a silver or glass hook, until it comes in contact with the elevated ledge which is to support it. The plate is to be completely covered with the nitrate of silver when thus lowered upon its support, which need not be more than a quarter of an inch above the bottom of the dish. Naturally, when the plate is in this position, the collodion is nowhere in contact with the vessel which contains it, excepting at the upper and lower edges. By making the above-mentioned ledge still more shallow, a very small quantity of the silver solution will suffice to cover the plate, and the solution can be filtered, if necessary, after each operation; whereby there can be but small risk of any damage from the deposition of particles of undissolved matter upon the film of collodion. In this country, the vertical or slightly inclined sensitizing baths are preferred, and consequently in most general use; in France and Germany, the horizontal baths are frequently to be met with, and are certainly to be recommended in order to avoid the trouble above alluded to.

To the right of the silver-bath for collodion-plates is the appropriate place of the horizontal dish to contain the sensitizing solution for the chloridized paper. This dish will have a capacity to meet the requisitions of the establishment, and may contain a whole sheet, a half-sheet, or even less, as the case may be. On a small shelf two feet above this dish are placed, in separate bottles, the plain silver and the ammonio-nitrate of silver solutions, a small filtering stand and funnel, ammonia, alcohol, and distilled water; and running from the dish to the southern side is constructed an inclined plane with a semicircular groove covered or lined with plates of glass or porcelain, each one overlapping its fellow like tiles. The first one just projects over the edge of the dish. This grooved inclined plane is screwed to the eastern side of the room, and being thus tiled, is situated in the right position for receiving the droppings of nitrate of silver from the sensitized sheets when removed from the dish, and attached by pins through an upper angle to a soft wooden slip immediately above. The first sheet that is taken from the bath is fixed at the most distant point, and so that the lowest angle is just in contact with the uppermost inclined glass tile; the next is pinned close to it, until the row is complete. If the lower corners or angles of the silvered paper touch the glass, the superfluous fluid will easily flow off and down the inclined plane into the dish; if the corners curl up, it will then be necessary, with a small pad of cotton-wool or a glass rod, to remove the accumulated solution, by bringing the corner in contact with the grooved channel. By this arrangement the photographer is able to economize his time and his solution. As soon as one row is thus filled with sensitized papers, those first pinned up will probably be sufficiently dry for removal to another slip situated on the southern side of the dark-chamber, thus making room for a fresh quantity of papers.

The semicircular grooves of glass can be manufactured as follows: Take, for instance, a piece of iron plate about fifteen inches long and two inches wide, and get it hammered longitudinally into a hollow groove; next cut up slips of glass of the same length, and about an inch and a half wide. Place one of these slips of glass in the iron channel so that it lies uniformly in the middle. Now heat the iron carefully red-hot, when it will be found that the glass will soften, sink, and assume the shape of the mould. When this has succeeded, allow the iron to cool gradually, in order that the glass may be properly annealed. By arranging these cylindrical glasses so that they overlap each other about half an inch, in the form of tiles, there is no need of applying cement.

WORK-ROOM.

The collodion can be kept on a small shelf in the darkroom, close by the door, in a very convenient place to seize when occasion requires. With this convenience, the plates are flowed in the doorway between the two rooms. At the north end of the work-room there is a good, large window, with the lower part about two feet from the floor, flush with the upper part of a shelf or table constructed right across, from side to side. On the sides of the window-frame, on nails or hooks, hang the various-sized mats for cutting albumen, etc., papers or photographs, as well as the different-sized plate-holders, diaphragms, pliers, scissors, diamonds, rulers, brushes, pencils, etc., used in mounting, printing, etc. On the left side of the table, on small shelves, are kept acetic acid, nitric acid, hydrochloric acid, sulphuric acid, protosulphate of iron in crystals, distilled or rain-water, citric acid, pyrogallic acid, alcohol, pestle and mortar, stirring-rods of glass, weights and scales, graduated measure for drachms and ounces, another for minims and drachms, cyanide of potassium, hyposulphite of soda, gun-cotton, iodide and bromide of cadmium, iodide and bromide of ammonium, nitrate of silver, ammonia, chloride of ammonium, gum-arabic, gelatine, solution of gum-arabic, etc., brush, spatula, and burnishing-tool, carbonate of lime, chlorinetted lime, acetate of soda, phosphate of soda, iodine, iodide of potassium, bromide of potassium, bichromate of potassa, and other chemical materials for experimentation. The preceding articles have to be arranged on narrow shelves in the order in which they can be most conveniently laid hold of, according to their respective merits as necessary or accessory ingredients. On the right side of the window arrange the various-sized glasses, already cut, bath for negatives and positives, the patent plate-holder or vice for cleaning glass plates, rotten-stone, alcohol, solution of salts of tartar, dilute solution of nitric acid, cotton or linen rags, patches of Canton-flannel, silk cloths, broad camel-hair pencil for dusting off particles or fibers from the polished glasses, triangular file, alcohol-lamp, shell-lac for mending the glass-corners, box of pins, box of tacks, small hammer, large and thick glass plate for cutting out photographs, etc., scale and compasses, vignette-glasses, the different-sized printing-frames, varnish, mats, preservers, cases, transfer-liquid, leather, black paper or velvet, etc., mounts of various sizes.

The sides of this room are furnished with wooden strips to which photographs can be attached by pins in order to dry them after fixation and washing. The toning and fixing dishes are situated on the shelf on the west side; as are also the chloride of gold, test-paper, nitrate of uranium, acetate and phosphate of soda, rain-water, alcohol, and hyposulphite of soda. Beneath the shelf place the tubs for washing prints. In drawers preserve the different sorts of paper in use. Have one drawer for dry but uncut positives, one for the cut positives, one for uncut stereographs, one for the right stereographs and one for the left, one for card-pictures not cut, and one for the prepared card-pictures. One writing-desk near the door and between the door and the window, for containing the day-book, etc. Photographic stock can be stored away on shelves on the southern end and oil the sides of this room. Both these rooms are to be supplied with stoves or other means of warmth and ventilation. On the entrance-door affix the sign forbidding all intrusion. Keep all visitors in the antechamber, which must be made comfortable, and somewhat artistically furnished for their reception. The photographer can not perform his duties with ease if crowded with inquisitive, meddling, and talking parties; the lenses do not operate well if the air is saturated with vapor, and the health is impaired in the midst of the mixed effluvia arising from degenerate lungs.