PhotoHistory

From: THE PRACTICAL PRINTER
A COMPLETE MANUAL PHOTOGRAPHIC PRINTING

By Charles W Hearn, 1874

PORCELAIN PRINTING

MAKING THE PORCELAIN COLLODION

I will below give a formula for the making of the collodio-chloride which I know to be good, having used it for more than two years, and I can truly say that I never knew a batch of this collodion to fail any one who has ever used it, providing it was properly mixed in the making of it.

If the porcelain collodion is not carefully mixed and made, it is the most fickle of all collodions.

The purest of chemicals and great care are required, both in the mixing together of the different solutions and in always keeping the collodion when it is made in absolute darkness, else it will be worthless, for if it is exposed to the light it will become discolored, and a chemical action is commenced which will, in a short time, render it as worthless as so much dirty water.

For this reason photographers, to guard against the actinic light getting at the contents of the bottle, should not only keep it in a dark place, but wrap printed and untoned paper around it, so that every part of the bottle will be covered, and only a little of the neck will show; and no more of that than what is required for the purpose of pouring the contents out, so as not to have the collodion touch the paper. The writer generally uses a couple of thicknesses of yellow envelope paper.

Another thing for the beginner to bear in mind is that he should always mix the different solutions, in the making of the collodio-chloride, a drop or two at a time, and no more, for then the solutions will be more likely to get mixed together than if you were to pour them in quicker. As a rule, always bear in mind that the slower the solutions are mixed together the longer time will the collodion keep in a good condition.

Then again, always handle the bottle of collodion as gently as possible, so as not to shake the contents any more than is really necessary.

Mix the solutions in the order given below, and never otherwise.

When ready to make the collodion, first proceed to make up four solutions, which will be stock, and which will at some future time enable you to make up more collodion in a short time, as you will only have to take a certain quantity of each of the stock solutions and mix them together.

A. — Plain Collodion
Alcohol, 95%, 7 ounces
Ether, 9 ounces
Gun-cotton, 112 grains

B. — Silver Solution

Nitrate of Silver, 480 grains
Distilled Water, 1 ounce

C. — Calcium Solution
Chloride of Calcium, 128 grains
Alcohol, 95%, 4 ounces

D. — Citric Acid Solution
Citric Acid, 128 grains
Alcohol, 95%, 4 ounces
Label each of these bottles, and state plainly what the contents of each bottle consists of, and exactly how it was made, in fact, write the whole formula on each label.

Obtain a ten-ounce collodion bottle which is thoroughly clean, and rinse it out with a little ether. Carefully decant 8 ounces of A, after it has been standing for a few days, into this bottle, and next add 64 drops of B, adding but two or three drops at a time, shaking well between each addition to prevent the silver from precipitating.

Now add in the same way 4 drachms of C, adding two drops at a time. This last addition is the most important of all, for the moment a drop of this is added, it will commence to turn milky, and chloride of silver is formed. This last addition should be done in the dark, and it would be well for the beginner to heed it, for from this time until the collodion is used up, the bottle should always be kept in the dark.

Finally, there should be 4 drachms of D added in the same manner as the calcium.

The beginner must bear in mind that chloride of silver is far more sensitive to the light than nitrate of silver, besides giving a softer, finer, and more delicate print than the latter.

It is on this account that the paper which is used in the positive process is salted generally with chloride of ammonium, although chloride of barium is sometimes used, so that we have a paper prepared which, when floated upon a bath of nitrate of silver, the chloride in the paper will take up from the bath the silver which it needs and form chloride of silver, which will print, as before said, much better than nitrate. Now the same thing is the case in the making of the collodio-chloride, with the exception that we cannot prepare the porcelain plate with a chloride as in the case of the paper, neither can we float or swab the plate successfully. To overcome this, we make a collodio(n)-chloride which will in its composition combine all of the nature of the albumen or the plain salted paper and the nitrate bath. The chloride of calcium, in conjunction with the nitrate of silver in the collodion, will form a chloride of silver, which is just what we wish. The plain collodion in the above collodio(n)-chloride is to give a tough body (when viewed in one direction) to the solution, which body is increased or diminished according to the number of grains of cotton there may be to the ounce of collodion, and to prevent it from getting thicker than it is already; then keep this plain collodion, as well as the collodio-chloride bottle, tightly corked.

The nitrate of silver in the above solution answers the place of the positive nitrate of silver bath, and the chloride of calcium, which is the chloride I always use, takes the place of the chloride of ammonium in the paper, and the chloride of silver (which is formed by the nitrate of silver and the chloride of calcium uniting) in the collodion is the same as the chloride of silver which is formed in the paper when floated upon the nitrate bath.

To get a richer tone to the freshly silvered paper, as well as to coagulate the albumen and prevent the solution from penetrating too far into the paper, alum, nitrate of ammonium (especially the former), are generally used, and to get a richer tone in the collodio-chloride, citric acid is used in the quantity recommended above.

In place of using the chloride of calcium, many photographers use the chloride of lithium or strontium, but I have always liked the calcium best, although I cannot say that I have given either of the above (i. e., lithium or strontium) a very fair trial. The chloride of calcium, however, is the most used of the above-named chlorides.

When the collodion is well made, it will have a most delicate pearly whiteness to it, which is the most beautiful color of that kind that I ever saw.

It can be worked with good results in a day after it is made, but it is in fine working order in about a week. I have used it when it has been four months old, and with the exception, in hot weather, of a very slight tinge of yellowness, it has been all right.

If porcelain collodion is made to keep for a long time, the greatest pains should be given in adding the silver and calcium to the collodion so as to have it properly mixed. It should be made more sensitive in winter than in summer, and for the beautiful imitation, the “photo-porcelain,” it would be better if the proportion of chloride of silver were six grains instead of eight, as the shadows in the making of this style of picture are more given to bronzing than in the real porcelain, but for the porcelain itself eight grains is the best.

COATING, FUMING, AND DRYING THE PLATES

COATING

The plate, when albumenized, is then to be coated with the collodio-chloride.

For this purpose, take the plate to a room where there is not too much white light, for instance in the “dark-room,” when the door is slightly opened. Brush away the dried collodion film and whatever dust there may be around the cork, being careful not to shake the contents of the bottle while doing so.

Hold the plate with the left hand, level to the floor, having hold of the lower left-hand corner, and take up the bottle of collodion in the right, and remove the cork with the teeth, if you have previously neglected to do so.

Pour the collodion at the center of the upper part of the plate until that half is covered, and then discontinue. Let the collodion flow over to the corners of the plate as I have recommended in Albumenizing the Plate, and when the collodion is ready to be poured from the plate, take up another collodion bottle (which should be kept expressly for this particular purpose) and let the collodion flow into that.

There is a knack in doing this, which consists in letting the plate lie almost level to the floor until the greater part of the collodion has flowed into the bottle, then the plate is raised more perpendicular, and gently rocked sideways, so as to prevent parallel lines forming in the direction of the corner from which it was flowed, which it would do if precautions were not taken to prevent it.

If the collodion is flowed from the plate too quickly, it will be too thick on the bottom of the plate, and if the rocking of the plate is not commenced before the collodion has begun to set, the parallel lines will show in spite of all the subsequent rocking. In drying, however, it will about all disappear.

If the plate is properly coated, it will have an even layer of collodion all over the surface, and will not be at all “streaky,” but on the contrary very smooth.

Flow close to the edges and corners of the plate, being careful that it does not run over the sides. Do not remove the collodion which may be a little thick along the sides nearest the corner at which it was poured off, as it will be a great aid in keeping the collodion from “peeling off.”

Keep gently rocking the plate until the collodion is thoroughly set, which is easily determined by placing the finger gently at the corner from which it was poured off, and if the collodion does not adhere, but leaves a mark of the impression of the finger, then you may know that the film is set.

FUMING

The plate, while still moist, is to be fumed. This can be done in the ordinary fuming-box. Hang up the plate by one of its corners to a spring nipper, and place three or four drachms of the strongest aqua ammonia in a saucer, which saucer is placed under the plate, on the bottom of the box. Fume from two to three minutes, and no more, and then the plate is ready to be removed.

DRYING

This should be done by gentle heat. The plate should be stood up, by support of a side of the negative oven, on one of its corners, and the door is closed. This oven should be heated with a tiny jet of gas which is capital for the purpose.

When the plate is dry, which it will be in a very few minutes, then remove it immediately, and set it away in a cool place until it cools.

If the plate is permitted to get too hot, then the heat will cook the albumen, also collodion, and it will cause the film to be ruined before you have even commenced to print on it, turning it to a very yellow color. Watch the plate while it is in the oven, so that you will not forget it and have the above-named ruinous results occur. It would perhaps be better for the beginner to hold the back of the plate for a minute or so in front of the door of a hot stove, if he cannot dry it in the oven without forgetting and thus baking it. Baking may be a good thing for “the staff of life” but it is not particularly so for collodionized porcelain plates.

Do not take hold of the plate, if it should happen to be very hot, either with wet, damp, or very cold fingers, as the plate will be liable to break.