EXPOSURE OF THE PLATE.
The plate having become sufficiently coated is taken from the bath, well drained, and placed in the holder or shield, and a piece of glass of the same size put behind it, which is to receive the pressure of the spring on the door of the holder, and force the plate into its proper position evenly, so that all parts will be in focus.
The holder containing the plate is then taken to the studio, or light room, where the subject, we will say, has already been posed; the camera set and focused, the exposure is then made, after which it is returned to the dark room for development.
DEVELOPER AND DEVELOPMENT.
In the preparation of a developing solution for plate pictures, we must consider that we desire to produce a picture, which, to be admired, must have p19 pure whites, clear shadows, be full of detail and have an easy gradation of light and shade.
That you may succeed in this object, use the following formula, and persist until you have learned its every modification:
DEVELOPER.
| Water | 64 ounces f. |
| Protosulphate of iron | 4 |
| Acetic acid | 4 |
| Alcoholic solution of tannin, 10 grains to the ounce | 4 |
The four ounces of iron should be dissolved in the sixty-four ounces (fluid) of water, and the acetic acid and tannic alcohol added.
In using this solution, develop your plate over a large filter, which will receive all your surplus developing solution, and conduct it into a bottle for use again; drain the plate into this filter before washing, wash carefully and then place it into the fixing solution—the developing solution which has filtered through into the bottle is afterwards used in the proportion of one-half of old to one-half of the new or fresh solution. This greatly improves the high lights of the picture, and by using more or less of the old solution, effects can be produced that are impossible by any other means.