PhotoHistory

THE PRACTICAL PRINTER
A COMPLETE MANUAL PHOTOGRAPHIC PRINTING

By Charles W Hearn 1874

THE POSITIVE BATH FOR ALBUMEN PAPER.

To prepare the paper so that it will become sensitive to the light it is necessary to float it upon a positive nitrate of silver bath; so called on account of its being the means by which the paper is enabled to receive the positive impression from the negative. This bath is chiefly composed of crystal nitrate of silver and pure water. The strength should vary, according to the temperature of the weather and the brand of paper used.

Mr. John B. Clemons recommends for his brand of albumen-paper a bath of thirty grains of nitrate of silver to the ounce of water, for summer, and forty-eight grains strong for winter; besides varying the time of floating the paper, according to the time of the year.

In the year 1871 there was considerable discussion in the leading photographic publications as to whether a strong or a weak bath was best for printing. Many of the leading photographers were in favor of a strong, and about as many more in favor of a weak bath.

It might be supposed that a weak silver bath would necessitate a longer time for floating than a strong bath would, and also that a bath weak in the number of grains of silver to the ounce of water would be more economical.

Now, this is a mistake. When a sheet of salted albumen-paper is floated upon a bath of nitrate of silver, the salt in the albumen will take up the silver which it needs, whether the bath is a strong or a weak one, and chloride of silver will be formed. The albumen will also take up some in the form of albuminate of silver (Yogel’s “Handbook”); and then, if the sheet is allowed to remain on the bath too long a time, there will be more of the solution absorbed than what is really necessary, which will penetrate through the surface and far into the albumen . The paper thus floated and printed will have a sunk-in appearance, owing to the silver discoloring, which is absorbed far into the albumen, as before said, during the lengthened time of sensitizing.

This sunk-in appearance is not the only fault with long floating on a weak bath; but the albumen will be dissolved off, being left in the bath, and the paper will not print brilliant, but dull; and often flat prints will be the result.

A strong bath necessitates a long time of floating, because the albumen on the paper is at first coagulated by the strong silver solution, and it takes quite a number of seconds for the albumen to commence to take up what silver it needs; whereas the albumen on the paper, not being coagulated by the silver in a weak bath, it will more readily absorb that silver which is necessary for the production of a good print.

From this we find :

• 1st. That a strong silver bath requires a long time of floating.
• 2d. That a weak silver bath requires a short time of floating.
• 3d. That a medium silver bath requires a medium time of floating.

There are, however, bad results obtainable by floating the paper a long time on a strong bath, as well as floating a short time on a weak bath.

When we float it a long time on a strong bath, it will, when printed, make a bold and brilliant print, but the shadows will be very much bronzed, even when the prints are mounted. When we float the paper a short time on a weak bath it will not be at all bronzed, but the prints are likely to be weak; and, on the other hand, if we float the paper a long time on this kind of a bath, the silver will be, as has been said, sunk-in, or, as it is sometimes expressed, the paper will be “woolly.”

I do not mean by the first two remarks made above that the extremes are to be indulged in, for then, in a measure, arises the bad results named, and in the case of the weak bath the abuse of the remark will be more especially a source of failure.

We cannot, to obtain good results, use a bath weaker than 35 grains, or stronger than 60 grains of silver to the ounce of water, with many of the brands of paper which are generally used, while with other brands, 30 grains in summer and 60 to 70 in winter are best.

For the excellent brand of paper known as the “Berlin” I found, with the class of negatives I printed when using that paper, that a medium-strong bath, say of 40 grains in summer and 55 to 60 grains in winter, of nitrate of silver to the ounce of water, was best; while with the “Hovey” brand of paper a bath of not more than 33, or less than 28 grains of silver to the ounce of water, with 25 seconds floating, was necessary during the summer-time; and in the winter, when the negatives are printed on the roof, I have known of a bath of 70 grains of silver alone, and from 2 to 3 minutes’ floating, to be required to obtain good prints from the very thin negatives that were made.

A weak bath loses so much, after silvering a dozen sheets or so, that it commences to make itself felt, and consequently needs strengthening about all of the time.

A strong bath loses also, but the silver is not taken up in so large a proportion as it is in the weak bath, and the strong bath can be used for a much longer time, even until there will not be enough solution to sensitize the paper, without giving the printer any trouble whatever.

The prints will be better in many respects with an average bath than with either the extremes, as a trial will show to the observant printer.

All of the solution that is on the paper should be, as much as possible, on the surface of the albumen, to prevent “woolliness,” and so as to have bold, vigorous prints; which can be easily freed from the nitrate of silver in the washing.

In the making of the bath, both good nitrate of silver and water are required. In all cases where pure water is required, filtered rain or clean ice-water will answer.

To make a bath of 60 ounces of solution, and 40 grains strong of nitrate of silver to the ounce, the number of grains of silver required would be 2400 grains, or 5 ounces.

Take a large, wide-mouth bottle and add 60 ounces of pure water thereto. Now carefully weigh out 5 ounces of good nitrate of silver and add it to the water in the bottle. Dissolve thoroughly, by repeated shakings of the contents of the bottle, which is very easily done without spilling the liquid, by holding the top of the bottle firmly with the left hand and revolving the bottom in a circular motion, in a steady and even manner, with the right.

This bath is called “plain nitrate of silver bath,” because of its being composed simply of nitrate of silver and water.

This bath is used by a great many excellent photographers throughout the country, except that the strength of it differs, sometimes being greater and then again often less than the strength given above.

Mr. H. T. Anthony, of New York, was the first to advise the use of alum in the printing-bath, and since the discovery of it for that purpose it has become quite universally used. It is, indeed, the best thing that can be added to the bath to give brilliancy and richness of tone to the prints. The theory of the alum, as being an improvement when used in the printing-bath, is as follows :

The alum hardens the surface of the albumen-paper when it is floated upon a silver bath containing it, so that the solution is kept more on the surface, and when the paper is quickly dried the resulting prints appear very brilliant, printing finely, especially in the shadows, and are more easily and better toned and fixed, and the final washing is more likely to be thoroughly done.

A small lump of alum is placed in the funnel through which the bath is filtered, and the solution, as it filters, will take up the quantity it needs.

Mr. John K. Clemons has recommended the use of glycerin in the printing-bath, in the proportion of 1 ounces of pure glycerin to every 16 ounces of solution. It has been used most successfully by many photographers, and it is especially a good thing for his brand of paper, when it is floated for the space of one minute on a bath of 30 grains (during the summer-time) of nitrate of silver to the ounce of water.

Sal soda is often added to the silver bath in the proportion of an ounce of a saturated solution of the soda to a bath of sixty ounces. On adding this the bath will immediately turn milky, and after the solution has been thoroughly stirred it should be allowed to settle for awhile and then filtered into another bottle before use, leaving the carbonate of silver (the deposit) in the first bottle. When through silvering the paper, pour the solution back into the bottle where the deposit is and again shake the contents. In the morning the solution will be thoroughly clear, although the bath may have been very much discolored when it was poured into the bottle the night before.

Always let a sediment be in the bottle, and every other day add a few drops of the soda solution to the bath. Keep on “adding solution” made up as above. A few ounces of the solution should be added to the printing-bath every night after use, so as to keep the quantity up to a certain number of ounces.

I have used a bath prepared as above for eight months, and although the bath, when poured from the silvering-dish at night, was often as black as a coal, it never failed to be clear in the morning, if there was a sediment on the bottom of the bottle.

Citric acid is also sometimes added to the printing-bath, in a greater or less degree, according to the time the paper is required to be kept, for this is principally the reason why the acid is added.

When the paper is only required to be kept a day or so after sensitizing, so as to prevent it from turning yellow by being kept over night, on account of a sudden storm, &c., the solution is made a very little acid, viz., a few drops of a solution of citric acid, 20 grains, water 1 ounce. If the paper is desired to be kept white for a longer time than a couple of days, then more of the acid should be added (see Chapter V, Part I). Fume fifteen minutes. The paper will print a little red, but it will most probably be very rich, although this will be according to the quality of the negatives, &c.

The “citric acid printing-bath” should be tested every morning before using it, to ascertain the degree of acidity. Never let your bath be acid with nitric acid unless it is very, very slightly so, as the prints besides being of a poor (photographically considered) red color are very liable to be weak and flat.

Nitrate of ammonia is very often added to the printing-bath in the proportion of as many grains of the nitrate to the ounce of water as there may have been grains of nitrate of silver added. After adding the nitrate of ammonia to the printing-bath make slightly alkaline with liq. ammonia.

Sunning the bath for about half an hour or so after the nitrate of ammonia has been added and the solution made alkaline is a good plan. Filter before use. I will here give a few formulae for baths for printing which I have used and know to be excellent.

No. 1.
Crystal Nitrate of Silver, 40 grains
Nitrate of Ammonia, 35 grains
Filtered Rain-water, 1 ounce
Saturated Solution Bicarbonate of Soda, about 8 to 10 drops

or enough to make the bath slightly alkaline. In place of the sodium, liquid ammonia can be used equally as well.

Make up a sufficient quantity, and before filtering through cotton place a lump of alum in the funnel about quarter the size of an ordinary butternut.

The above bath is for summer use; in the winter, both the nitrates should be increased.

No. 2.
Nitrate of Silver, 2-1/2 ounces
Nitrate of Soda, 2 ounces
Glycerin, 3 ounces
Pure Water, 40 ounces

Make it a little alkaline with aqua ammonia. This bath is very good, indeed, for the demons brand of paper, and can be used also with the Hovey brand, but a bath made as below is better for this particular paper, viz., the Hovey :

No. 3.
Nitrate of Silver, 30 grains
Nitrate of Ammonia, 30 grains
Pure Water, 1 ounce

Make it a little alkaline with aqua ammonia, and when about to filter the solution place a small lump of common alum in the funnel, or if you prefer add a grain of the alum to every ounce of the solution. The latter is probably the best. The alum, if added in this way, should be added before the bath is filtered.

Float the paper, being sure that it is a little damp beforehand, from twenty to thirty seconds; draw over a rod, and blot off the superfluous quantity of silver that is still on the paper, between large sheets of white bibulous paper. Dry quickly and thoroughly, and fume ten minutes.

The above formulae and modes of working are for summer use, but for winter the temperature of the solution should not be below 50 degrees, and the strength of the nitrates should be increased as well as the time of floating. Print, in the winter, in the printing-room under glass, and keep the temperature of the room not below 50 degrees or above 60 degrees.

There are some photographers who prefer an acid positive bath to an alkaline or a neutral one, because the resulting prints are red, and the red tone is more easily obtained (?), so they say.

If the bath is acid with nitric acid the result will not be so fine as it would be if it was acid with citric acid, because, if the bath was any more than very slightly acid with the nitric, the paper floated upon it when printed will have, as above said, a disagreeable red tone to it, often being weak and flat. The best results are obtainable with a bath which is either a trifle alkaline or just neutral. A good way to regulate the alkalinity of the printing-bath is to observe how the paper prints, and then act accordingly.

If it prints too blue, a drop or so of nitric acid should be added to the bath; if it prints too red then add a few drops of liquid ammonia. In testing this way, however, the printer should be sure that the paper is properly fumed, and that the results are not occasioned by poor judgment in fuming. Place a piece of blue litmus-paper into the solution before you commence to “doctor” the bath, and note the exact color it turns.

Nitric acid should always be added to the positive bath when it is not desired to make the solution acid for the purpose of printing, but only to lessen the alkalinity of the bath.

RECTIFYING THE POSITIVE BATH.

The bath, after it has been used for some time, discolors, owing to the albumen of the paper being left in it after floating, or dirt and other impurities having got into it through accident; leaving the dish uncovered when the bath was not in use, imperfect nitrations, and chemical matter which was impure, and by age having showed itself.

Permanganate of Potash.

When the bath is only a little discolored, and is a new one, this solution will for awhile answer capitally :

Permanganate of Potash, 60 grains
Pure Water, 6 ounces

Add about half a dozen drops, and stir the solution well with a clean glass rod. At first the bath will turn a dark rose color, and it will then considerably lighten, and if it does not stay so, but utterly disappears, then add a few drops more until a temporary color appears. Now place the bath out in strong sunlight for half an hour, and after it has thoroughly cleared, and the rose color has disappeared, the organic matter can, in a great measure be filtered out.

Mr. Elbert Anderson in his book, The Skylight and the Dark-Room, accounts for~the action of this permanganate as follows :

As soon as the permanganate comes in contact with the bath the organic matter becomes oxidized, and permanganic acid is liberated, forming permanganate of silver, which remains in the bath, and is precipitated to the bottom in dark, brownish-black flakes, whilst the permanganate itself is converted into peroxide of manganese. As soon as the solution is perfectly clear most of the organic matter will be filtered out. Thus the permanganate precipitates most of the organic matter without the least injury to the bath.

Kaolin.

This is often used for clearing up the printing-bath. A little of this powder is placed in the bottle containing the discolored bath, and the solution thoroughly stirred with a glass rod, and then allowed to settle for the space of a few minutes. Filter the decanted solution through cotton, and at night pour the bath again into the bottle containing the kaolin. Thus the same kaolin can be used for a great number of times.

Mr. F. A. Bridge, in The Year-Book for 1873, recommends for those printers who use the kaolin a simple apparatus described as follows :

Take a large wide-mouthed bottle (depending upon the quantity of solution you have in use), fit a cork to it, and bore three holes in it, one large enough to admit the point of a funnel, going well through the other side, and the other two large enough for a piece of ordinary glass tube. Bend a piece of tube in the form of a siphon, let one end reach to within about an inch of the bottom of the bottle, and let the other end be a few inches longer; break it off below the turn in the longest side, and join it together again by means of a piece of india-rubber tubing about two inches long; put another piece of glass tube (slightly bent for convenience sake) just through the cork, and the thing is made. Put some kaolin in the bottle, and after using the solution return it to the bottle through the funnel over night, and shake it; it will be quite clear by the morning. When again required for use you have only to cover the top of the funnel, put the long end of the siphon in the dish, blow gently down the short tube, and the siphon immediately commences to act, and eoninue6 to do so while there is any solution to supply it; and, if care is taken to stop it before the top of the solution reaches the level of the siphon-tube (which may be done at any time by pressing the piece of india-rubber tube), no scum will ever get into the dish.

Gum Camphor Solution.

When the bath is very much discolored this rectifier is most generally used. It is made as follows:

Gum Camphor, 1 ounce
Alcohol, 95 percent, 6 ounces

Add about four drachms of this solution to the discolored bath, and shake well. Probably the frothiness which is at first formed will disappear, and then it will be necessary to add another equal quantity, if not more; shake well, and then allow the bottle to stand for a few minutes without being shaken. Filter the solution through paper, and the albumen, which united with the camphor, will be left in the filter, and the bath will be very clear,

Boiling down the solution.

About once a month or so the printing-bath should be boiled down about two-thirds. It is first made very alkaline with aqua ammonia, and is then placed in an evaporating-dish over a small gas stove, and a small jet of gas turned on. When it has boiled down two-thirds turn off the gas, and permit the solution to cool gradually, leaving the dish on the stove in the meantime.

When cool, filter through paper, and test the strength of the silver by means of Pile’s test-tube and solution. Add water to reduce the bath to that strength which is best for the paper, negatives, &c. Then add the other nitrates (or whatever other chemicals that might have been used in the making of the bath in the first place) to the bath, see to the alkalinity, filter, and the bath will be ready for use.

Fusing the Bath.

Place the bath in a suitable size evaporating-dish, and boil down to dryness at a gentle heat. Scrape the silver which has adhered to the sides of the dish down to the bottom, and stir the solution with a glass rod until all the bubbling has ceased. Now turn off the gas jet, and stir the mass constantly with a glass rod until it has cooled, and then the mass will be broken up, which is a more desirable state to have it in. In an hour or so after you have left off stirring it, you can dilute the strength of the fused mass by the addition of pure water.

Reduce to the proper strength for the printing-bath, and then filter the solution. The organic matter will be left in the filter. Now make up your bath as has before been advised, and then it is ready for use.

Sunning the Bath.

The bath is made alkaline and placed out in the sunlight, for the purpose of throwing down the organic matter in it.

The bath is very much improved by sunning, and it should always be placed out in the light when not in use.

To prevent evaporation, keep the bottle tightly closed.

Filtering the Bath.

This can be done either by means of common filtering-paper or through cotton.

Good filtering-paper can be obtained from almost any stock dealer, of various sizes, all prepared for immediate use. Sometimes the filtering-paper is rendered useless on account of there being traces of hypo-sulphite of soda in it, but this is very seldom the case. If you have a filtering-paper of which you are suspicious, you can test it by the following simple method:

Take a sheet of the suspected lot of paper, and place it in a small and perfectly clean evaporating-dish, in which there has been placed a small quantity of warm distilled water, say five ounces. Cover the dish over with a glass, and let the paper soak for a few hours, and then boil the water, still with the paper in it, for the space of half an hour.

Take a clean test-tube, and squeeze about an ounce of the water from the wet paper into it. This should be done with perfectly dean hands.

Now dissolve about five grains of permanganate of potash in about an ounce of distilled water, and then add ten grains of bicarbonate of soda to it.

When this solution is thoroughly dissolved and mixed, then let fall about three drops of it into the test-tube containing the water squeezed from the filtering-paper.

If there is a trace of the hypo-sulphite in the water, the liquid in the test-tube will turn a more or less greenish tint, according to the quantity of the soda there may be in the solution. Look sharp.

If there be no hypo-sulphite there, the rich color of the test solution will not be lost, although its deepness may be weakened. When the latter is the case, the filtering-paper does not have anything in its composition that will be at all injurious to the bath when filtered through it.

When preparing to filter your bath solution through paper, the paper should be folded in six or eight places, so as to permit the air from the bottle to escape between the folds of the paper, and thus allowing the solution to filter quicker. In folding, be careful that you do not break the center of the sheet of filtering-paper, at which the folds meet

The paper should be placed in the funnel, and when the solution is poured into it to be filtered, it should be poured at the side of it, slowly at first, so that the weight of the solution will not be likely to break the filter.

When it is desired to filter the bath through cotton, the cotton should be wet thoroughly with good common alcohol, and thrown into the funnel.

Now pour the solution in, and filter the bath. If it filters too quickly, ie., imperfectly, then press the cotton down further in the neck of the funnel; if too slowly, then place the glass rod in the center of the filter, turn it round once or twice, so as to catch hold of the cotton, and then pull it up very slightly.