Sometimes in parts of the plates, the developing seems to stop, some of the shadows will remain white. This may mean insufficient exposure, which is not easily remedied. In many cases, however, it will help matters if the solution is returned to the graduate, and then slowly poured on the spot, repeating this if necessary. Or a little more of the alkali may be added to the solution. If too much is added it may produce fog. For soda developer it will be well to keep on hand a saturated solution of carbonate soda, made by dissolving three ounces in five ounces of hot water. A few drops of this may be sufficient to hasten development and bring out detail. A saturated solution is a so lution containing all of the solid that the water will dissolve.
The active element in the developer, the pyro, hydrochinon etc., gives contrast and intensity; the alkali gives detail and harmony, and hastens the development.
A developer in which equal parts of Nos. 1 and 2 are used, works better in winter than summer. In warm weather it is well to weaken somewhat the solution and especially the No. 2, which is the alkali, remembering always that heat accelerates, while cold retards, development.
In detective views, and generally in instantaneous work, fresh solutions work best. With instantaneous exposures, we think that decidedly the best negatives are obtained by first soaking the plate a few minutes in a very weak solution of sal soda or carbonate of potash, or both combined. This has the effect of softening the film. After this it is best to commence with a weak developer which can be changed for a stronger solution after the details have appeared. There should be no attempt to develop such exposures quickly, but give them plenty of time. Old developer can be used for long exposures. In winter views, where there is strong contrast, use less of No. 1 and give plenty of time to the developing. If in any view there is great want of contrast add caustic soda in developing with hydrochinon to make it act quickly.
If in doubt as to the exposure the plate has received, it is safer to begin developing with a weak solution when using pyro. If the plate is known to be over-exposed let it soak first in the pyro solution a few minutes, and then add the alkali slowly. Or if the exposure is known to be too short soak first in the alkali, and add the pyro slowly till the development is complete. Hydro chinon will act quite as fast as pyro if it is used without a pre servative like sulphite of soda.
A good motto for the dark-room would be " Keep graduates, funnels and trays, perfectly clean, and don't hurry." In developing plates, especially very rapid ones, it is always best to have only one in the tray at a time. Of course, if the tray is only large enough to hold one plate no one will try to de velop two in it at once, but you may some time have a number of small plates to develop, and may think it economical of time to place two in the tray, side by side. If both are quick plates they may have had different exposures, and one may develop much faster than the other, so that when you remove them from the dark, (where the development is begun) to place them under the lantern, one of them may be so nearly finished that you may wish to keep it there while you watch the details com ing out; and at the same time in the other the image may be only just beginning to appear, in which case, while the light from the lantern will not injure the one nearly developed, it may slightly fog the other.
After the plates have been placed in the fixer, a dim lamp or gas light will not injure them. The writer was developing a number of plates and had them all, as he supposed, developed and fixed, and, after placing them on the washing-board, turned up the gas, when he was surprised to find that one had not been fixed at all. He took it out of the wash and placed it in the hypo. without changing the light, and the plate fixed as well as any of them.
If a negative is over-intense, it may be due to too strong a de veloper, or to too long development. Thinness may be caused by either over-exposure or under-development. As such acci dents are always liable to happen, the amateur will sometimes have a thin negative which needs intensification, or one too in tense which should be reduced. These defects may be general, covering the whole plate, or there may be changes needed only in certain portions. If the reader will kindly refer to the chapter on formulas, he will find directions for these manipulations. Before attempting to doctor a negative, locally, if it is a valuable one which cannot be readily reproduced, it will be as well to make a transparency from it, as from this a new negative can be made if the original should happen to suffer during treatment.
Fog in a negative, in which the image seems to be clouded or veiled, may come from a variety of causes. A leak in the camera may cause this, or an unsafe dark-lantern, or light getting into the plate-holder. A developer too warm may produce fog, or one containing too much carbonate of soda.
Spots on negatives may be due to dust on the plate, or bubbles in the tray, or to washing the plate before developing. Such spots should be carefully touched with some opaque color applied with a finely-pointed brush, moistening the color with mucilage. This color should be as nearly as possible like that of the negative; neutral tint, carmine and Prussian blue mixed carefully, will make the right tint. Gihon's opaque is also excellent for such pmposes.
As it is a very nice operation touching-out the spots in nega tives many photographers prefer to fill the spots with a color so dark that they will show as white spots in the prints. These spots are then more easily retouched, as the paper gives a better surface for the color, and the picture shows the exact tint re quired. Our illustration shows a very handy frame for retouch ing negatives.
Sometimes a bit of paper sticks to a negative, and it seems hn possible to remove it. In printing, perhaps, a wet finger care lessly touches the film and the paper adheres. To remove it lay the plate in water several minutes to soak, and then very gently rub the paper with the ball of the thumb or finger until most of the paper is rubbed off. The rest will come off by plac ing the plate for ten minutes in the hypo. bath, after which it can be washed and dried.
The film of a negative, after drying, should feel smooth to the touch. If it feels at all rough it shows that the hypo. has not been entirely removed in the washing, and the plate. should be carefully washed again for fifteen or twenty minutes.