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appear. Before the final focussing, the camera should be moved so that just the objects desired appear on the ground glass. To include more of the upper part of the landscape, the sliding front may be raised. If this throws some of the lower objects off the glass, the camera should be moved farther back. The focus is now made perfectly distinct for some one object in the middle foreground, the operator viewing its image carefully with the focussingglass. The images of more distant and nearer objects will probably now be a little blurred. To remedy this, one of the "stops" must be put on the lens. The largest should be tried first, and then a smaller one, till all parts of the picture are equally distinct. No smaller one than ab
solutely necessary should be used, as the smaller the stop, the less light falls on the plate. If there is an object in the very near foreground, it will be necessary to use the swingback to make its image distinct.
The cap must now be placed over the lens, the ground glass removed, and the plate-holder put in its place, the focussing-cloth being thrown over it as it is taken from the box where it is kept, and remaining over it till it is returned to the box. This is necessary that light may not reach the plate through some crack in the holder. The slide is withdrawn, and then the light is admitted to the plate by removing the cap from the lens, taking care not to shake the camera in so doing. When the exposure is finished, the lens is recapped, the slide returned, and the plate-holder replaced in its box.
For the time of exposure, no rules can be given. It must be determined in every case by experience, as it varies with the light, the lens, the plate, the stop used, and the kind of picture. The time may thus vary from almost nothing, with a very sensitive plate and bright light, to 10, 15, or 20 seconds with
poor light. In general a hazv or yellow light requires a longer time than clear weather, and the hours near noon less time than late afternoon. Spring foliage requires less time than the same in summer, and a sea view than a landscape. After the photographer has had experience he will judge of the time required by comparing the kind of view, the light, and the other conditions, with those of some previous picture he has taken. A second or two more or less is not fatal to success, but over-exposure is easier to remedy than under-exposure. The beginner should make several exposures of the same view, and note which one turns out best. The plate-holder should be marked after each exposure with the time, stop used, and other data to be remembered.
Developing. This process requires great care, and must be carried on in the dark room. There are many developing fluids, each of which has its advocates. The following directions show how to make one of the best. The solution is made in two parts, which are mixed as they are needed. Each may be held in a twelve-ounce bottle. The following chemicals are needed:
Sulphite of soda, crystals, 1 lb. Carbonate of potash, granulated," Carbonate of soda," Pyrogallic acid, 4 oz.
Bromide of potash, 1"
Solution 1. Dissolve two ounces, by weight, of sulphite of soda in eight measured ounces of soft water, add slowly half a dram of sulphuric acid, and then 240 grains of pyrogallic acid. Pour in enough water to make eight ounces of mixture. In warm weather fifteen grains of bromide of potassium may be added to prevent too rapid working. This solution is labelled "Pyro." It must be used only so long as it is perfectly clear.
Solution 2. Dissolve one ounce each of carbonate of potash and soda in five ounces of water. Add enough water to make eight ounces.
Each solution should be poured into its bottle through a wad of clean cotton placed in a funnel.
When the developing solution is needed, the two solutions are mixed and diluted, in the proportion of one part of each to two parts of water.
To develop the plate, lay it in one of the trays, face upward, and pour the solution over it with a sweeping motion. Then move the tray so that it will be washed evenly, gently breaking all air-bubbles with the finger-tip. The picture will shortly begin to appear on the plate, the very light parts first (which of course are black in the negative). If the plate is under-exposed, the details of the picture will refuse to appear; if over-exposed, the whole picture will appear suddenly. The negative should be examined by holding it up to the light from time to time, and as soon as the details are distinct enough, the plate is thoroughly washed with a stream of clear water from the rubber tube. If it is known beforehand that a plate is over-exposed, only half the ordinary quantity of the second solution is used, and a few drops of a solution of bromide of potash are added (50 grains to the ounce of water). The bromide makes the process slower, the second solution hastens it; so by varying the proportions, a developer may be made to suit a plate more or less over-exposed.
Fixing. Two solutions are needed for fixing: one composed of one part of alum to ten of water, the other of one part of hyposulphite of soda (called " hypo " for short) to five of water. The trays for fixing should be about two inches deep, and enough solution is placed in each to cover a plate. When the negative has been washed, after developing,
it is placed in the alum solution for four or five minutes, washed again, and then in the "hypo" solution till no whiteness is seen on the plate, looked at from the back. This should take not more than ten minutes; the '• hypo " should be renewed if it works slowly. Fixing may be carried on in a weak light, and after it is finished the plates may be exposed to strong light without injury. If the fixing is not thoroughly done, however, the negative will not last. After fixing, the plates are placed in a large pail of water, for several hours, the water being changed every twenty or thirty minutes, and they are then allowed to dry, without being heated.
Varnishing. This is not necessary unless the plates are to be preserved a long time. Prepared varnish (to be bought of a dealer in photographic supplies) is poured on the plate, which is lowered first at one end and then at the other, so that the varnish flows evenly over the surface. The surplus is drained into the bottle from one corner, the plate being rocked to and fro to prevent drying in ridges.
Printing. Paper all ready for printing may be bought, or it may be prepared by soaking albumenized paper in a bath of nitrate of silver, composed as follows:
Water, 64 ounces.
Nitrate of silver, 8"
Ammonia, one drop to each
This solution is used over and over again, adding nitrate of silver and ammonia from time to time. The condition of the solution may be tested by putting enough shot into a glass tube closed at one end to float it upright in a bottle of the liquid. Make a scratch on the tube at the level of the liquid. As the latter gets weaker the tube will sink lower, and enough nitrate of silver
darker than the finished picture is tD be. After printing, the pictures most be washed in clear water, which is changed thrice, letting each time about ten
This process changes the of the print from reddish brown to brownish black. A stock station should first be made by dissolving 15 grains of chloride of gold and sodium in 15 ounces of water. To make a toning bath for twenty prints, add three ounces of this to 10 ounces of water in which have been dissolved a pinch of cooking-soda and a pinch of common salt. The bath must be kept slightly alkaline, and should be tested with litmus paper (see Test Papersi. If it does not turn red litmus paper blue, more soda should be added. The prints are to be toned, about a dozen at a time, by laying them one by one face downward into a tray partially filled with the bath. It should be seen that thev do not stick together. The bath should be kept at a temperature of about 700. which in a cold room may be done by setting the tray on a hot-water bottle. In ten or fifteen minutes the red color of the prints will turn to a purplish or brownish black. If the process is kept up too long they will become slate-colored.
If the prepared silver-paper be used, the following recipe gives better results: Add to the gold solution a solution of cooking soda, drop by drop, till it turns red litmus paper blue. Add 10 grains of acetate of soda and 18 ounces of water.
Fixing the Prints. Soak them fifteen or twenty minutes in a bath formed by dissolving in one gallon of water a pound of hyposulphite of soda and a tablespoonful each of cooking-soda and common salt. The part used should be thrown away. After fixing, the prints should be soaked three or four minutes in strong salt and water. They should then be thoroughly washed, the water being changed eight or ten times.
Blue Prints. These are made on blue or cyanotype paper (Greek, cyanos, blue). The process of printing is as already described, the paper, as manufactured, being all ready to put into the printing-frame with the negative. No toning and fixing is necessary, the print requiring only to be washed in pure water till the drippings cease to be yellowish.
Hydrochloric acid makes the color bluer, and sulphuric acid renders it greenish. A few drops of either are sufficient. Ammonia turns the color to purple and makes it lighter.
The ease of blue printing has made it popular with amateurs, and many use it for taking "proofs" even when they desire to print afterward in the regular way.
Bromide Prints. Bromide of silverpaper is very sensitive, and is used where quickness is sought and for enlargements. The paper is so sensitive that thin negatives are best printed by the light of a kerosene lamp. To enlarge a picture, the negative should be fixed in a hole in the wall in front of a Hf.uostat. and a lens so placed that a sharp enlarged image of the negative is thrown on the sensitive paper, which is supported on an upright board. No light should enter the room except that which comes through the lens.
The print does not show at first, but requires to be developed, so that it cannot be told directly when the printing is finished, as with an ordinary photograph. The photographer must learn the proper time for exposure in various cases by experience, as in taking the picture.
Bromide prints are developed and fixed as follows: The developer is made by mixing three solutions, which are kept on hand separate
Solution 1. One pound of oxalate of potash to three pints of hot water.
Add sulphuric acid till it turns blue litmus paper red.
Solution 2. One pound of protosulphate of iron to one quart of hot water. Add one-half dram of sulphuric acid.
Solution 3. One dram of bromide of potassium to one quart of water.
Just before developing, mix six ounces of No. 1 and one ounce of No. 2, and use cold. No. 3 is used to restrain the action in over-exposure, but too much of it spoils the print. The developer, when mixed, should be of a clear dark red. If turbid, it is unfit for use. The image appears slowly. When it is done, wash the print several times in a solution of one ounce of citric acid in a quart of water, then rinse in pure water, and finally f x in a solution of three ounces of "hypo" to a pint of water. Fixing takes about ten minutes. Wash the print, place it in the alum bath, and then wash again. Dry by hanging on a line, not between blotters. Bromide prints last much longer than ordinary ones. They may be used for book illustrations, without mounting, by soaking in five ounces of glycerine mixed with twenty-five ounces of water.
Mounting. Before mounting, the print should be trimmed to the desired shape, which is generally done by laying on it a glass or metal form and cutting around the edge. A knife may be used, but specially made cutters, formed of a small wheel, are preferable. The print should be laid, when cutting, on a piece of glass covered with paper. Glass alone dulls the cutter, and wood is too soft.
The prints are secured to the cardboard mounting with paste, which must be very smooth and free from lumps. All air-bubbles must be pressed out from between the print and the card, and no more paste used than is absolutely necessarv.
Burnishing. After mounting, the
scape should not be photographed from the shadow side, as it appears too sombre. The best time for taking landscape views is in the morning or early afternoon, but late afternoon is the best time for cloud
A land- that ordinarily a damper
against each wire, which is raised the corresponding key 3: hence the feather only those wires to sound which are undampened. The wires must be lightly brushed, as otherwise all of effects. When a body of water them might sound, in spite of the appears in the picture, a point of dampers.
3. Press down one key. gently.
view should be chosen where the water will not appear as a sheet oi white. Distant views are best taken when the air is clear and free from haze or smoke, though a partially cloudy sky gives an excellent light.
Flash-Light. Places which are always too dark to photograph by sunlight may be taken by flashlight. Magnesium "cartridges " to
before, and then strike the one an octave below it, very hard, not holding it down. When the sound has been sufficiently dampened, the pressed-down key will be heard sounding clearly. The reason is. that the note struck is composed of several notes, being in fact a chord, and these cause the corresponding
produce this light may be bought; wires to vibrate in sympathy. The of dealers in photographic material, other notes which will vibrate in In using them, focus must first be like manner are the fifth above the made with the aid of lamp or gas- . octave, the second octave, and the light. The lens is then capped, the 1 third and fifth above that. These slide drawn, all lights put out, the
lens uncapped, and then the car tridge is lighted, making a sudden, short, and brilliant light.which takes the picture. The lens is then recapped and the plate removed.
PIANO, Experiments with a. The Piano is described in C. C. T. The following experiments can be performed by anyone who understands the elements of music.
f. Place sheets of music on the wires. The notes will now have a ratling sound, and a tune on the piano
are called overtones. Thus, if a C in the lower part of the piano be struck, any or all of the following notes will sound, if their keys be first pressed down and held down.