2. Is the iodine dry? If the impressions come out blue, you may rest a.s.sured it is not. Take out the iodine, wipe and dry the box, and dry the calcium.
3. Is the quick battery of the right strength? If dry, it must change the plate in from six to fifteen seconds. If any of the chloride of iodine cla.s.s, it may vary from five seconds to a minute. Begin by coating light, and increase on each trial, observing the effect. If the light side of the picture seems loth to come out, and shows no contrast with the dark side, it is to be inferred that your battery is too strong, and must be reduced with water or set out in the open air for a few minutes, with the lid off. If working an old battery, never renew very strong, or it will work dark and heavy. A battery, to work well, should be gradually losing strength, but never gaining. An old battery, however, may be quickened up and made to work well for some time, by adding five of six drops of sulphuric acid, repeating the quant.i.ty as often as necessary, providing always that acid be not used in manufacturing the quick.
4. Have the plates lost their sensitiveness by being many times exposed to mercury? Clean and burn them; but if French plates, burn light, or you spoil them.
5. Are the buff s dry and clean? Examine the plate critically after buffing to detect any appearance of sc.u.m or film on the surface. If so, the longer you buff the more it shows. Sc.r.a.pe and dry the buffs thoroughly.
6. Is the mercury free from sc.u.m and dirt? If not, filter. Is it also far enough from the coating boxes? Should be at least three feet, and kept covered.
7. Is the mercury sufficiently heated? This is important. Long exposure, however, will answer the same purpose.
8. Are your lenses clean, and in proper place?
9. Are the tablets in focus with the ground-gla.s.s? If you can attribute the failure to none of these, mix a new box of some other kind of quick, say the dry, for instance. If you fail in the same manner here, take time, wash your buffs, overhaul all the chemicals, and start anew. Do not be discouraged.
There is no day so dark but that the sun will shine again. We will close with this brief summary of advice:
Clean your plates. Keep everything dry. Keep the mercury hot. Follow these instructions carefully, and you must succeed.
HINTS AND CAUTIONS.
First of all, cleanliness should be observed. When there is dust or dirt about your room, particularly about the work-bench, failures will be frequent; for the smallest particles of rotten-stone, when allowed to come in contact with the buffs, will produce scratches on the surface of the plate, which very much injures the operation, and often causes failures.
Dust flying about the room is injurious, if allowed to fall on the plate, either before or after it has been coated, as it causes black spots which cannot be removed.
The polished plate should not be allowed to come in contact with a strong current of air, for it tends to oxidize the surface. Breathing on the surface should also be avoided, for the same reason.
The plate should, in all cases, be buffed immediately before using, and not allowed to stand any length of time. It should be held with the polished face downward.
It is always best that the plate should be of the same temperature of the atmosphere in the room.
Keep the camera and mercury-bath perfectly free from the vapors of iodine and bromine; for the presence of the slightest degree of either of the above will injure the impression in no small degree. As a preventive, let the camera be exposed to the sun or fire for a few minutes in the morning.
Filter your mercury often, to keep the surface free from film and dust.
The hyposulphite solution should be filtered through sponge every time it is used.
The direct rays of light must not enter the camera in conjunction with those reflected from the object; or the picture will be veiled, and the color of the plate changed to a thick green.
If the plate be iodized only to a light-yellow, the result might be of a bluish or grey tinge: and this is generally the case, when the quick is new and strong, and there is an excess of it on the plate, and yet not enough to form the bromide iodide of silver; in which case it would wholly spoil the impression.
Your iodine will be found to operate more successfully, when the time required for coating the plate does not fall short of fifteen seconds, or exceed one minute.
Too quick coating can be avoided by using less iodine in your box. In the summer months, when the weather is 80 deg. and over, one quarter of an ounce, or even less, will work to advantage.
ELECTROTYPING.
I am indebted to Mr. J. H. Fitzgibbons for the following process, which he employed in producing the excellent specimens he exhibited at the Crystal Palace:
"I shall endeavor to lay down in as comprehensive a manner as possible the method by which I have been enabled to produce the most satisfactory results. I use a Smee"s battery (another kind will do).
After filling the cell, of common size, nearly full with water; add about quarter of an ounce of sulphuric acid. Mix this well, and let it stand for about three hours, or until the action of the battery becomes weak, when it is in order to work with a very uniform action. Put one pound of sulphate of copper in one quart of water; stir it until the sulphate of copper is all dissolved, and then add one half ounce of sulphuric acid and a quarter of an ounce of nitric acid. This solution, well mixed, should be filtered, and it is ready for use. It is very important that the solution should be kept clean, clear, and free from all foreign substance. The above quant.i.ty of this solution will be found sufficient for electrotyping a dozen of the sixth-size plates. When it is required to be strengthened, it is only necessary to add a little of the sulphate of copper.
"With the battery prepared as above, and the solution of sulphate of copper in a vessel of proper dimensions to receive your plate, connect the galvanic current, and immerse the impressioned plate, letting it remain until a thin film of copper has been formed, then the battery can be strengthened, and the impression will be of sufficient thickness to be removed in from eight to twelve hours. An old Daguerreotype plate attached to the opposite pole of the battery (copper side towards the face of the plate to be electrotyped), will answer the same purpose as the silver-plate.
"The great difficulty in taking an electrotype impression, and preserving the original, has been attributed to the battery being too powerful. I am led to believe from practice that the princ.i.p.al difficulty has been in the Daguerreotype plate itself, for if we use an impression that has been taken but a few days, and taken in the usual way, we will find it difficult to succeed without spoiling both the copy and original, and so also with an old impression.
"I have found the most certain method to be as follows:--Coat the Daguerreotype plate as usual, except use less of the accelerators, the proportion of iodine coating being greater, of course the time of exposure in the camera will be lengthened. Mercurialize it at about a temperature requiring to develop the image, from six to eight minutes, at least. Gilding the Daguerreotype has much to do towards producing a good electrotype copy. This should be done by applying a little heat, and gilding very slowly, giving a coating of gold with the greatest possible uniformity. By this method, I have been enabled to produce any number of proofs. I have produced a dozen from one impression, and it remains as perfect as when first taken.
"By a little judgment and care the operator will be enabled to produce the electrotype copy of the Daguerreotype plate without any difficulty.
The electrotype copy should be immediately put under a gla.s.s and sealed in the same manner as the ordinary Daguerreotype."
CRAYON DAGUERREOTYPES.
This process is patented in the United States, by J. A. Whipple, of Boston, and of course no honorable person will use it for his own benefit without purchasing a right.
A white back-ground is generally employed, the object being to blur the lower portion of the plate, leaving the head of the subject in relief.
Every Daguerreotypist is familiar with the fact that a motion of any body between the camera and the sitter will cause a "blur." Cut a piece of thin paper and scallop it, making a semicircle. This is kept straight by means of a wire frame, and it is to be moved in front of the lower part of the body of the sitter during the time of exposure of the plate in the camera. Develop over mercury as usual, and the result will be a crayon Daguerreotype.
Another method is to have a wheel with a hole cut through it of a diameter of about 12 inches. This hole is so cut as to leave teeth resembling those of a large saw. This wheel is so arranged that it can be turned around, which should be done during the time of exposure in the camera. It must be placed between the camera and the sitter, and at such a distance from the camera as to allow such proportion of the body of the sitter be seen upon the ground-gla.s.s as is desired. It will be readily seen that by turning this wheel during the operation will produce the same result as the paper being moved in the other method. The teeth make the "blur." The side of the wheel towards the camera may be black, by which means the result will be a dark instead of a light border.
ILLUMINATED DAGUERREOTYPES.
This process is also patented, and the remarks on the preceding subject will apply in this case. The plate is prepared and exposed as in the usual method of the Daguerreotype. A white back-ground is employed.
Let the head of the sitter come in the middle of the plate, and before exposing it to the vapors of mercury, put a small mat or diaphragm, having a small hole through it, over or directly on the surface of the plate. This diaphragm should be bevelled, and the bevel should be towards the surface of the plate; this, in order to prevent too sharp a line on the impression. It will be readily seen that if an impressioned plate so covered is placed over the mercury, it will be developed on such portions only as are exposed. The principle is so familiar that further explanations are unnecessary.
NATURAL COLORS IN HELIOGRAPHY.
This subject is worthy the attention of every operator. The following process is so plain and easy of trial that any Daguerreotypist can try it. This is as given by Mr. James Campbell, and was published in Humphrey"s Journal of the Daguerreotype and Photographic Arts, vol. 5, page 11. Mr. Campbell has done much to further the process announced by M. Neipce, and his experiments have proved highly successful.
The following is submitted as worthy of trial:
"The proper preparation of the chloridated plate, to enable it to receive colored impressions is an object of the first importance to those wishing to experiment on it, and consequently requires particular notice. The plate may be prepared by making it the positive pole of a battery, and letting it at the same time be immersed in chlorine water.
The negative pole should be a slip of platinum. All the colors may be produced from a plate so prepared if the chlorine and water are in the right proportions; but generally one color or the other predominates, according to the amount of chlorine in the liquid. By adding the chlorides of strontian, uranium, pota.s.sium, sodium, iron, or copper to the liquid, various effects may be produced, and these bodies will be found to produce the same color on the plate that their flame gives to alcohol.
"The honor of this discovery is due to M. Neipce. Copper gives a variegated flame; hence many colors may be impressed on a plate prepared with a solution of its chloride.
"M. Neipce recommends a solution of the mixed chlorides of copper and iron, and it is with these, that I have been most successful. As the chlorides of copper and iron are not much used in the arts, they are not generally found for sale in the shops; and it may be well to furnish those not much versed in chemistry with an easy method of preparing them.
"They may be made directly from either metal by dissolving it in hydrochloric acid; but they may be formed by a cheaper method, and by which also the acid fumes are avoided.
"Sulphate of iron or copper, or both together, may be dissolved in water and then neutralized with common crude potash, or its carbonate or bicarbonate--known commonly as pearl ash and saleratus. If either of the latter be used, there will be formed sulphate of potash and a carbonate of the metal used, and there will also be a considerable effervescence of carbonic acid, which will, if care is not taken, cause the mixture to run over the vessel. After the copper or iron salt is neutralized, which is known by its ceasing to effervesce, the carbonate of the metal will settle slowly, and will at first nearly fill the vessel. The supernatant fluid, which is sulphate of potash in solution, may now be carefully poured off, and its place filled with water; this operation should be repeated several times until the water which pa.s.ses off is tasteless. The carbonate of the metal rapidly changes to an oxide by contact with the air, and it will generally be found, when it is sufficiently washed, that it is at least half oxide.
On adding hydrochloric acid cautiously to the mixture, a chloric of the metal will be formed, and carbonic acid will be evolved from the remaining carbonate. The chloride formed is soluble; but as there are two chlorides of these metals, and we wish to produce the one which contains the most chlorine, it is best to add the acid cautiously until the solution is decidedly acid. After filtering the solution, it is fit for use; and it should be preserved in well-stoppered bottles. The water used should be rain or distilled water.
"About one part of the mixed chlorides should be used to three or four of water.