It frequently happens that the amateur in outdoor photography requires a plate which will retain its sensitiveness for a few hours, such as the photographing of objects within easy reach of his home. This can be accomplished in a most satisfactory way, without resort to dry-plates or tent, by proceeding in the usual manner as regards coating and sensitising the plate, and, after thoroughly washing it, applying the following preservative solution: -
Glycerine...... 12 dr.
Albumen .. .. .. 2 oz.
Water .. .. .. .. 4 oz.
Ammonia...... 2 drops
No special collodion is required, and the formula is easily made up and applied. As to developing the plate, a 4-gr. solution of pyrogallic acid will be found sufficient; and when all the details are well out, intensification with pyrogallic acid and silver will secure a good negative. Plates so prepared will keep moist for at least 4 hours in moderately warm weather.
In case the subject to be photographed is within a mile of dark room, and provided the weather is cool, the ordinary wet plate, without any preservative, will answer, as, by attending to the following hints, the plate will keep moist for at least 20 minutes. After taking the plate from the bath, place it in the dark slide, in a horizontal position, and carry it in that position to the camera, and, after exposure, bring it back to the dark room in the same position and develop at once. A small piece of blotting-paper must be placed in each corner of the dark slide, to prevent any of the silver solution flowing over the plate, and a piece of damp blotting-paper should be placed on the back of the plate, to prevent evaporation as much as possible. Give a little longer exposure than you would under ordinary circumstances, and use a little more alcohol in the developer.