| Sodium hyposulphite | 2 | ounces |
| Water | 20 | " |
The washing after fixing is more rapid than with albumenized paper. It is washed in ten or twelve changes of water for ten minutes, and then placed for five minutes in an alum bath made as follows:—
| Potash alum | 5 | ounces |
| Water | 20 | " |
The print is washed in a few changes of water, and the prints are ready for drying and mounting. The advantage of the alum bath is that the hyposulphite is destroyed into harmless products, and the gelatine is rendered insoluble by it. In the formula given there is large excess of chloride, and we recommend that instead of using 2,440 grains of barium chloride, 2,050 grains be used. (Mr. Wilkinson has used that amount of the barium salt that would be required exactly to convert 1,700 grains of silver nitrate into silver chloride, if the formula for barium chloride were BaCl3 instead of BaCl2.) It will be seen that whichever formula is used, there is no silver left to combine with the gelatine, and hence the image will be entirely formed by metallic silver, and not an organic salt of silver.
[CHAPTER XXI.]
DRYING THE PRINTS.
In many establishments the prints are taken direct from the washing water, and hung up by American clips, and thus allowed to dry. When this is done, the prints curl up as the water leaves the paper, and they become somewhat unmanageable. If prints have to be dried at all before mounting—and they must, unless they are trimmed before toning—a better plan is to make a neat heap of some fifty or sixty of the same size (say cartes), place them on blotting-paper, and drain for a time, and then in a screw-press (such as is used to press table-cloths, for instance) to squeeze out all superfluous water. After a good hard squeeze the prints should be separated, and the plan adopted by Mr. England carried out. He has frames of light laths made, of about 6 feet by 3 feet, and over this frame is stretched ordinary paperhanger's canvas. The prints are laid on this to dry spontaneously, and they cockle up but very little. The frames, being light, are easily handled. After the squeezing is done, supposing the room in which they are placed be not very damp or very cold, the prints will be ready for trimming and mounting in a couple of hours. To our minds there is nothing superior to this mode of drying, since the squeezing in the press tends to eliminate every slight trace of hyposulphite which might be left in them.
Trimming the Prints.—Perhaps more prints are ruined in trimming than in any other way, when the operator is inexperienced, since it requires judgment to know which part of the print to trim off, so that a right balance shall be kept. In trimming landscape prints, it is impossible to give any set rules; the judgment as to what is artistic must be the guide. Of one thing we may be certain, that, unless the operator who took the original negative knows exactly how to balance his picture on the focussing-screen, the print will always bear cutting down in one direction or the other. Such a clipping, of course, alters the size of the print, which, if it be one of a series, will be a misfortune; but, on the other hand, the artistic value of the individual print will be increased.
For portraits there are some few rules which should be followed in trimming. Always allow the centre of the face to be a little "out" from the central line of the print, making more space on the side towards which the sitter is looking. Allow a carte or cabinet to be cut in such a way that, if the sitter has been leaning on something, it does not seem as if he had been leaning on nothing. Should there be an unintentional lean on the part of the sitter, trim the print so that he appears in an upright position.
To trim the print, there should be the various sized shapes in glass used. Thus there should be glasses with bevelled edges for the carte, the cabinet, and other sizes, which can be laid on the print as a guide to the trimming. The absolute trimming may be done either by shears or by a knife, a leather cutters' knife being excellent, since it is rounded, and can be brought to a keen edge very readily. When the knife is used, the print is placed on a large glass sheet of good thickness, the pattern placed over it, and, whilst this is held down by the left hand, the knife is used by the right, keeping it close to the edge of the pattern glass. When shears are used, the print is held against the pattern glass by the left hand, and each side trimmed by one clip, taking care to make the cut parallel to the edges of the pattern glass. It requires a little practice to prevent clipping the glass as well as the paper, but for small sized prints, such as the carte, the shears have a decided advantage over the knife.