Henley's Twentieth Century Formulas, Recipes and Processes
Part 99
«Pigment Paper for Immediate Use.»—Pigment paper is usually sensitized in the bichromate solution on the evening before it is desired for use. If it is not then used it will spoil. By proceeding as follows the paper may be used within a quarter of an hour after treating it in the bichromate bath. Make a solution of
Ammonium bichromate 75 grains Water 3 1/2 fluidounces Sodium carbonate 15 grains
Mix 0.35 ounces of this solution with 0.7 ounces alcohol, and with a broad brush apply to surface of the pigment paper, as evenly as possible. Dry this paper as quickly as possible in a pasteboard box of suitable size, 15 minutes being usually long enough for the purpose. It may then be used at once.
«Photographing on Silk.»—China silk is thoroughly and carefully washed to free it from dressing, and then immersed in the following solution:
Sodium chloride 4 parts Arrowroot 4 parts Acetic acid 15 parts Distilled water 100 parts
Dissolve the arrowroot in the water by warming gently, then add the remaining ingredients. Dissolve 4 parts of tannin in 100 parts of distilled water and mix the solutions. Let the silk remain in the bath for 3 minutes, then hang it carefully on a cord stretched across the room to dry. The sensitizing mixture is as follows:
Silver nitrate 90 parts Distilled water 750 parts Nitric acid 1 part
Dissolve. On the surface of this solution the silk is to be floated for 1 minute, then hung up till superficially dry, then pinned out carefully on a flat board until completely dry. This must, of course, be done in the dark room. Print, wash, and tone in the usual manner.
«TONING BATHS FOR PAPER.»
The chief complaints made against separate baths are (1) the possibility of double tones, and (2) that the prints sometimes turn yellow and remain so. Such obstacles may easily be removed by exercising a little care. Double tones may be prevented by soaking the prints in a 10 per cent solution of common salt before the preliminary washing, and by not touching the films with the fingers; and the second objection could not be raised provided fresh solution were used, with no excess of sulphocyanide, if this be the bath adopted.
A very satisfactory solution may be made as follows:
Sodium phosphate 20 grains Gold chloride 1 1/2 grains Distilled (or boiled) water 10 ounces
This tones very quickly and evenly, and the print will be, when fixed, exactly the color it is when removed from the bath. Good chocolate tints may be obtained, turning to purple gray on prolonged immersion.
Next to this, as regards ease of manipulation, the tungstate bath may be placed, the following being a good formula:
Sodium tungstate 40 grains Gold chloride 2 grains Water 12 ounces
The prints should be toned a little further than required, as they change color, though only slightly, in the hypo. {541}
Provided that ordinary care be exercised, the sulphocyanide bath cannot well be improved upon. The formulas given by the various makers for their respective papers are all satisfactory, and differ very little. One that always acts well is
Ammonium sulphocyanide 28 grains Distilled water 16 ounces Gold chloride 2 1/2 grains
For those who care to try the various baths, and to compare their results, here is a table showing the quantities of different agents that may be used with sufficient water to make up 10 ounces:
Gold chloride, 1 gr. to 1 oz. water 12 dr. 16 dr. 16 dr. 11 dr. 11 dr. 14 dr. Borax 60 gr. Sod. bicarbonate 10 gr. Sod. carbonate 20 gr. Sod. phosphate 20 gr. Sod. tungstate 40 gr. Amm. sulphocyanide 17.5 gr.
We may take it that any of these substances reduce gold trichloride, AuCl_〈3〉 to AuCl; this AuCl apparently acts as an electrolyte, from which gold is deposited on the silver of the image, and at the same time a small quantity of silver combines with the chlorine of the gold chloride thus:
AuCl + Ag = AgCl + Au
When toning has been completed, the prints are washed and placed in the fixing bath, when the sodium thiosulphate present dissolves any silver chloride that has not been affected by light.
Besides the well-known, every-day tones we see, which never outstep the narrow range between chocolate brown and purple, a practically infinite variety of color, from chalk red to black, may be obtained by a little careful study of toning baths instead of regarding them as mere unalterable machines. Most charming tints are produced with platinum baths, a good formula being
Strong nitric acid 5 drops Water 4 ounces Chloro-platinite of potassium 1 grain
The final tone of a print cannot be judged from its appearance in the bath, but some idea of it may be got by holding it up to the light and looking through it. A short immersion gives various reds, while prolonged toning gives soft grays.
Results very similar to platinotype may be obtained with the following combined gold and platinum bath:
_A._—Sodium acetate 1 drachm Water 4 ounces Gold chloride 1 grain
_B._—Chloro-platinite of potassium 1 grain Water 4 ounces
Mix _A_ and _B_ and neutralize with nitric acid. (The solution will be neutral when it just ceases to turn red litmus paper blue.)
Another toning agent is stannous chloride. Two or three grains of tin foil are dissolved in strong hydrochloric acid with the aid of heat. The whole is then made up to about 4 ounces with water.
«Toning Baths for Silver Bromide Paper.»—The picture, which has been exposed at a distance of 1 1/2 feet for about 8 to 10 seconds, is developed in the customary manner and fixed in an acid fixing bath composed of
Distilled water 1,000 cubic centimeters Hyposulphite of soda 100 grams Sodium sulphite 20 grams Sulphuric acid 4 to 5 grams
First dissolve the sodium sulphite, then add the sulphuric acid, and finally the hyposulphite, and dissolve.
Blue tints are obtained by laying the picture in a bath composed as follows:
_A._—Uranium nitrate 2 grams Water 200 cubic centimeters
_B._—Red prussiate of potash 2 grams Water 200 cubic centimeters
_C._—Ammonia-iron-alum 10 grams Water 100 cubic centimeters Pure hydrochloric acid 15 cubic centimeters
Immediately before the toning, mix
Solution _A_ 200 cubic centimeters Glacial acetic acid 20 cubic centimeters Solution _B_ 200 cubic centimeters Solution _C_ 30 to 40 cubic centimeters
Brown tints. Use the following solutions: {542}
_A._—Uranium nitrate 12 grams Water 1,000 cubic centimeters
_B._—Red prussiate of potash 9 grams Water 1,000 cubic centimeters
And mix immediately before use
Solution _A_ 100 cubic centimeters Solution _B_ 100 cubic centimeters Glacial acetic acid 10 cubic centimeters
Pictures toned in this bath are then laid into the following solution:
Water 1,500 cubic centimeters Pure hydrochloric acid 5 cubic centimeters Citric acid 20 grams
«To Turn Blueprints Brown.»—A piece of caustic soda about the size of a bean is dissolved in 5 ounces of water and the blueprint immersed in it, on which it will take on an orange-yellow color. When the blue has entirely left the print it should be washed thoroughly and immersed in a bath composed of 8 ounces of water in which has been dissolved a heaping teaspoonful of tannic acid. The prints in this bath will assume a brown color that may be carried to almost any tone, after which they must again be thoroughly washed and allowed to dry.
«COMBINED TONING AND FIXING BATHS.»
The combined toning and fixing bath consists essentially of five parts—(1) water, the solvent; (2) a soluble salt of gold, such as gold chloride; (3) the fixing agent, sodium thiosulphate; (4) a compound which will readily combine with “nascent” sulphur—i. e., sulphur as it is liberated—this is usually a soluble lead salt, such as the acetate or nitrate, and (5) an auxiliary, such as a sulphocyanide.
The simplest bath was recommended by Dr. John Nicol, and is as follows:
Sodium thiosulphate 3 ounces Distilled water 16 ounces
When dissolved, add
Gold chloride 4 grains Distilled water 4 fluidrachms
A bath which contains lead is due to Dr. Vogel, whose name alone is sufficient to warrant confidence in the formula:
Sodium thiosulphate 7 ounces Ammonium sulphocyanide 1 ounce Lead acetate 67 grains Alum 1 ounce Gold chloride 12 grains Distilled water 35 fluidounces
A bath which contains no lead is one which has produced excellent results and is due to the experimental research of Dr. Liesegang. It is as follows:
Ammonium sulphocyanide 1/4 ounce Sodium chloride 1 ounce Alum 1/2 ounce Sodium thiosulphate 4 ounces Distilled water 24 fluidounces
Allow this solution to stand for 24 hours, during which time the precipitated sulphur sinks to the bottom of the vessel; decant or filter, and add
Gold chloride 8 grains Distilled water 1 fluidounce
It is curious that, with the two baths last described, the addition to them of some old, exhausted solution makes them work all the better.
«ENLARGEMENTS.»
─────────────────────────────────────────────────────────────────────────────── TIMES OF ENLARGEMENT AND REDUCTION ───────+────────+────────+────────+────────+────────+────────+────────+──────── Focus │ │ │ │ │ │ │ │ of │ 1 inch │2 inches│3 inches│4 inches│5 inches│6 inches│7 inches│8 inches Lens. │ │ │ │ │ │ │ │ In. │ │ │ │ │ │ │ │ ───────+────────+────────+────────+────────+────────+────────+────────+──────── 2 │ 4 │ 6 │ 8 │ 10 │ 12 │ 14 │ 16 │ 18 │ 4 │ 3 │ 2 2/3 │ 2 1/2 │ 2 2/5 │ 2 1/3 │ 2 2/7 │ 2 1/4 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 2 1/2 │ 5 │ 7 1/2 │ 10 │ 12 1/2 │ 15 │ 17 1/2 │ 20 │ 22 1/2 │ 5 │ 3 3/4 │ 3 1/3 │ 3 1/8 │ 3 │ 2 9/10│ 2 6/7 │ 2 3/16 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 3 │ 6 │ 9 │ 12 │ 15 │ 18 │ 21 │ 24 │ 27 │ 6 │ 4 1/2 │ 4 │ 3 3/4 │ 3 3/5 │ 3 1/2 │ 3 3/7 │ 3 3/8 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 3 1/2 │ 7 │ 10 1/2 │ 14 │ 17 1/2 │ 21 │ 24 1/2 │ 28 │ 31 1/2 │ 7 │ 5 1/4 │ 4 2/3 │ 4 3/4 │ 4 1/5 │ 4 1/12│ 4 │ 3 9/10 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 4 │ 8 │ 12 │ 16 │ 20 │ 24 │ 28 │ 32 │ 36 │ 8 │ 6 │ 5 1/3 │ 5 │ 4 4/5 │ 4 2/3 │ 4 4/7 │ 4 1/2 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 4 1/2 │ 9 │ 13 1/2 │ 18 │ 22 1/2 │ 27 │ 31 1/2 │ 36 │ 40 1/2 │ 9 │ 6 3/4 │ 6 │ 5 3/5 │ 5 2/5 │ 5 1/4 │ 5 1/7 │ 5 1/16 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 5 │ 10 │ 15 │ 20 │ 25 │ 30 │ 35 │ 40 │ 45 │ 10 │ 7 1/2 │ 6 2/3 │ 6 1/4 │ 6 │ 5 5/6 │ 5 5/7 │ 5 5/8 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 5 1/2 │ 11 │ 16 1/2 │ 22 │ 27 1/2 │ 33 │ 38 1/2 │ 44 │ 49 1/2 │ 11 │ 8 1/4 │ 7 1/3 │ 6 4/5 │ 6 1/2 │ 6 5/12│ 6 2/7 │ 6 3/16 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 6 │ 12 │ 18 │ 24 │ 30 │ 36 │ 42 │ 48 │ 54 │ 12 │ 9 │ 8 │ 7 1/2 │ 7 1/5 │ 7 │ 6 6/7 │ 6 3/4 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 7 │ 14 │ 21 │ 28 │ 35 │ 42 │ 49 │ 56 │ 63 │ 14 │ 10 1/2 │ 9 1/3 │ 8 3/4 │ 8 2/5 │ 8 1/6 │ 8 │ 7 7/8 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 8 │ 16 │ 24 │ 32 │ 40 │ 48 │ 56 │ 64 │ 72 │ 16 │ 12 │ 10 2/3 │ 10 │ 9 3/5 │ 9 1/3 │ 9 1/7 │ 9 ───────+────────+────────+────────+────────+────────+────────+────────+──────── 9 │ 18 │ 27 │ 36 │ 45 │ 54 │ 63 │ 72 │ 81 │ 18 │ 13 1/2 │ 12 │ 11 1/4 │ 10 4/5 │ 10 1/2 │ 10 2/7 │ 10 1/8 ───────+────────+────────+────────+────────+────────+────────+────────+────────
{543}
The object of this table is to enable any manipulator who is about to enlarge (or reduce) a copy any given number of times to do so without troublesome calculation. It is assumed that the photographer knows exactly what the focus of his lens is, and that he is able to measure accurately from its optical center. The use of the table will be seen from the following illustration: A photographer has a _carte_ to enlarge to four times its size, and the lens he intends employing is one of 6 inches equivalent focus. He must therefore look for 4 on the upper horizontal line and for 6 in the first vertical column, and carry his eye to where these two join, which will be at 30–7 1/2. The greater of these is the distance the sensitive plate must be from the center of the lens; and the lesser, the distance of the picture to be copied. To reduce a picture any given number of times, the same method must be followed; but in this case the greater number will represent the distance between the lens and the picture to be copied, the latter that between the lens and the sensitive plate. This explanation will be sufficient for every case of enlargement or reduction.
If the focus of the lens be 12 inches, as this number is not in the column of focal lengths, look out for 6 in this column and multiply by 2, and so on with any other numbers.
To make a good enlargement five points should be kept constantly in view, viz.:
1. Most careful treatment of the original negative.
2. Making a diapositive complete in all its parts.
3. Scrupulous consideration of the size of the enlargement.
4. Correct exposure during the process of enlargement.
5. The most minute attention to the details of development, including the chemical treatment of the enlarged negative.
The original negative should not be too dense, nor, on the contrary, should it be too thin. If necessary, it should be washed off, or strengthened, as the case may be. Too strong a negative is usually weakened with ammonium persulphate, or the fixing hypo solution is quite sufficient. All spots, points, etc., should be retouched with the pencil and carmine.
The diapositive should be produced by contact in the copying apparatus. A border of black paper should be used to prevent the entry of light from the side.
The correct period of exposure depends upon the thickness of the negative, the source of the light, its distance, etc. Here there is no rule, experience alone must teach.
For developing one should use not too strong a developer. The metol-soda developer is well suited to this work, as it gives especially soft lights and half tones. Avoid too short a development. When the finger laid behind the thickest spot, and held toward the light, can no longer be detected, the negative is dense enough.
The denser negatives should be exposed longer, and the development should be quick, while with thin, light negatives the reverse is true; the exposure should be briefer and the development long, using a strong developer, and if necessary with an addition of potassium bromide.
The silver chloro-bromide diapositive plates, found in the shops, are totally unsuited for enlargements, as they give overdone, hard pictures.
To produce good artistic results in enlarging, the diapositive should be kept soft, even somewhat too thin. It should undergo, also, a thorough retouching. All improvements are easily carried out on the smaller positive or negative pictures. Later on, after the same have been enlarged, corrections are much more difficult and troublesome.
«VARNISHES:»
«Cold Varnish.»—
I.—Pyroxylin 10 grains Amyl alcohol 1 ounce Amyl acetate 1 ounce
Allow to stand, shaking frequently till dissolved. Label: The negative should be thoroughly dried before this solution is applied, which may be done either by flowing it over the solution or with a flat brush. The negative should be placed in a warm place for at least 12 hours to thoroughly dry.
II.—Japanese gold size 1 part Benzol 1 part
Label: In applying this varnish great care should be taken not to use it near a light or open fire. It can be flowed over or brushed on the negative.
«Black Varnish.»—
Brunswick black 1 1/2 ounces Benzol 1 ounce
Label: The varnish should be applied with a brush, care being taken not to use it near a light or open fire. {544}
«Dead Black Varnish.»—
Borax 30 grains Shellac 60 grains Glycerine 30 minims Water 2 ounces
Boil till dissolved, filter, and add aniline black, 120 grains.
Label: Apply the solution with a brush, and repeat when dry if necessary.
«Ordinary Negative Varnish.»—
Gum sandarac 1 ounce Orange shellac 1/2 ounce Castor oil 90 minims Methyl alcohol 1 pint
Allow to stand with occasional agitation till dissolved, and then filter. Label: The negative should be heated before a fire till it can be comfortably borne on the back of the hand, and then the varnish flowed over, any excess being drained off, and the negative should then be again placed near the fire to dry.
«Water Varnish.»—It is not only in connection with its application to a wet collodion film that water varnish forms a valuable addition to the stock of chemicals in all-round photography; it is almost invaluable in the case of gelatin as with wet collodion films. In the case of gelatin negatives the water varnish is applied in the shape of a wash directly after the negatives have been washed to free their films from all traces of hypo, or in other words, at that stage when the usual drying operation would begin. After the varnish has been applied the films are dried in the usual manner, and its application will soon convince anyone that has experienced the difficulty of retouching by reason of the want of a tooth in the film to make a lead-pencil bite, as the saying goes, that were this the only benefit accruing from its application it is well worthy of being employed.
The use of water varnish, however, does away with the necessity of employing collodion as an additional protection to a negative, and is, perhaps, the best known remedy against damage from silver staining that experienced workers are acquainted with. As a varnish it is not costly, neither is it difficult to make in reasonably small quantities, while its application is simplicity itself. The following formula is an excellent sample of water varnish:
Place in a clean, enameled pan 1 pint of water, into which insert 4 ounces of shellac in thin flakes, and place the vessel on a fire or gas stove until the water is raised to 212° F. When this temperature is reached a few drops of hot, saturated solution of borax is dropped into the boiling pan containing the shellac and water, taking care to stir vigorously with a long strip of glass until the shellac is all dissolved. Too much borax should not be added, only just sufficient to cause the shellac to dissolve, and it is better to stop short, if anything, before all the flakes dissolve out than to add too much borax. The solution is then filtered carefully and, when cold, the water varnish is ready for use.
«FADED PHOTOGRAPHS AND THEIR TREATMENT:»
Restoring Faded Photographs.—I.—As a precaution against a disaster first copy the old print in the same size. Soak the faded photograph for several hours in clean water and, after separating print from mount, immerse the former in nitric acid, highly dilute (1 per cent), for a few minutes. Then the print is kept in a mercury intensifier (mercuric chloride, 1/2 ounce; common salt, 1/2 ounce; hot water, 16 ounces, used cold), until bleached as much as possible. After half an hour’s rinsing, a very weak ammonia solution will restore the photograph, with increased vigor, the upper tones being much improved, though the shadows will show some tendency to clog. The net result will be a decided improvement in appearance; but, at this stage, any similarly restored photographs should be recopied if their importance warrants it, as mercury intensifier results are not permanent. It may be suggested that merely rephotographing and printing in platinotype will probably answer.
II.—Carefully remove the picture from its mount, and put it in a solution of the following composition:
By weight Hydrochloric acid 2 parts Sodium chloride 8 parts Potassium bichromate 8 parts Distilled water 250 parts
The fluid bleaches the picture, but photographs that have been toned with gold do not quite vanish. Rinse with plenty of water, and develop again with very dilute alkaline developer.
«MOUNTANTS:»
See also Adhesives.
I.—If buckling of the mount is to be cured, the prints must be mounted in a dry state, and the film of mountant borne by the print must be just sufficient to attach it firmly to the mount and no more. The great virtue of the method {545} here described consists of the marvelously thin film of tenacious mountant applied to the print in its dry condition, shrinkage by this means being entirely obviated. A drawing board with a perfectly smooth surface and of fair dimensions, an ivory or bone burnisher attached to a short handle, with some common glue, are the principal requisites. Take, say, a quarter of a pound of the glue broken into small pieces and cover it with water in a clean gallipot, large enough to allow for the subsequent swelling of the glue. Place on one side until the glue has become thoroughly permeated by the water, then pour off the excess and dissolve the glue in the water it has absorbed, by placing the gallipot in a vessel of hot water. The solution tested with a piece of blue litmus paper will show a distinctly acid reaction, which must be carefully neutralized by adding some solution of carbonate of soda. The amount of water absorbed by the glue will probably be too little to give it the best working consistency, and, if this is the case, sufficient should be added to make it about the thickness of ordinary molasses. Careful filtration through a cambric handkerchief, and the addition of about 10 grains of thymol, completes the preparation of the mounting solution. As glue deteriorates by frequent and prolonged heating, it is preferable to make up a stock solution, from which sufficient for the work in hand can be taken in the form of jelly, melted, and used up at once.