Recreative Science: A Record and Remembrance of Intellectual Observation, Vol. II. Groombridge and Sons, Paternoster Row, London, 1861 p.119

THE PRINTING PROCESS IN PHOTOGRAPHY.

HAVING procured good negatives, it is important to be able to get good prints from them and, although the process of printing is a simple matter, we often see very bad prints taken from what are evidently good negatives; the operator seems to have paid all the care and attention he can to his negatives, end then to have hurried over the printing, thinking it of no importance. Those who have collected photographs for the last eight or ten years, cannot look over their portfolios without feeling considerable annoyance. many of the once beautiful specimens are now mere shadows in yellow and brown, many are spotted and partially faded, and comparatively few are in their original state. Fortunately the cause of this destruction is now well known, and we need not fear the fading of our photographs, if the printing be properly conducted. This is not the place to enlarge on the causes of fading; it will be sufficient to say that photographs toned or coloured with chloride of gold appear unalterable, and those coloured with sulphur, from the decomposition of the hyposulphite of soda bath, are almost certain. to fade in time.

The writer has some prints he toned with chloride of gold in 1852, which are as beautiful as on the day they were printed; whilst of those toned with hyposulphite of soda, or, as it was called. "old hypo," few are in existence, and none are in their original state. Unfortunately the latter process was used extensively from 1852 to 1858, being cheaper and easier to work than the other, consequently a large proportion of the prints produced between these periods have already faded, or will sooner or later do so.

The first process, "albumenizing the paper," is not worth the attention of an amateur, unless he have plenty of time at his disposal. "Papier saxe" albumenized is to be obtained very good; but it is well to try a sheet or two before procuring a supply, as there is a quantity of rubbish in the market, apparently coated with a mixture of albumen and glue, on which it is impossible to produce a good print. A pressure frame and three earthenware dishes will be wanted; also the following solutions:

Among the different modes of rendering the paper sensitive, the two following are perhaps the best, the first when a considerable number of papers are to be prepared, the second when only a few are wanted at a time:--

l. Pour the nitrate of silver solution into one of the dishes, float the sheets one at a time on the surface, taking care that there be no bubbles underneath; let the sheet remain four or five minutes, and then pin up to dry in the dark-room; the pins used should be coated with varnish.

FIG 1.--Bent Glass Rod.

2. When only a few prints are wanted the glass rod (Fig. 1) is the most convenient instrument to use; there is no waste of nitrate of silver, and all the requisites can be got out, the paper rendered sensitive, and the various articles replaced in a few minutes.

FIG. 2.--Preparing Paper with Glass Rod.

For papers 11 x 9 inches, measure out half a drachm of the silver solution into a clean glass, spread on the table a couple of sheets of blotting-paper, and lay the sheet to be prepared on it (Fig. 2); then with the right hand take the glass rod, and with the left pour on the solution, then move the rod over, the paper, driving the solution before it, and then backwards and to the edges, so as to wet the surface equally all over. Continue this until the paper has absorbed the fluid, and then hang it up in the darkroom to dry. With some descriptions of paper a little more than half a drachm is required; this can only be ascertained by trial.

A little practice is requisite to use the glass rod neatly; a beginner often presses too hard with the rod, and rubs up the albumen into a froth. A few trials are requisite, to show the amount of pressure required to distribute the solution without disturbing the surface.

When quite dry, the paper may be put into the pressure-frame with the negative, and printed until rather darker than it will be required when finished. Then wash the print in water several times, until the water used no longer looks milky; then place it in the toning solution in a dish, and agitate it a little.

The print rapidly changes colour, and when it is of the tone required, take it out and place it in the fixing solution for five minutes, and afterwards wash in many changes of water, and hang up to dry. The black or the sepia tone is owing to the print being a longer or shorter time in the toning-bath. The eight ounces of toning solution will tone five prints of 11 X 9 inches, after which it may be thrown away as worthless, all the chloride of gold having been abstracted.

If the photographs are mounted on card. board, or pasted into a book, freshly-made paste should be used for the purpose.