Sensitizing. The plate is now slowly and gradually lowered into the sensitizing solution, taking care not to stop it in the Least until it is thoroughly covered, lest streaks occur upon it. It may be same position. Before putting the plate in the holder, hold it up to the light a moment, to notice the density of the film, which should he perfectly smooth, creamy, not bluish, and semi - transparent. You will observe upon returning to the dark - room, after exposure, that the plate has gained considerable in density during the time it remained in the holder, bowing conclusively that the decomposition was still going on during exposure. - Elbert Anderson.
140. When a glass plate is coated with collodion and dipped into the nitrate bath, the salt - of iodine and bromine will decompose and iodide and bromide of silver (which are very sensitive to light) will take their places on the film, while a combination of nitric acid with a dam will remain in the bath. Dr. H. W. Vogel.
160. Observe that the plate should always be put in the plate-holder in the same direction in which it is put into the bath, and be careful at all times to keep the plate-holder in the "churned" " gently up and down while in the bath solution. When upon examination the film appears smooth and free from greasy - looking lines, it is ready for exposure, and, being placed in the dark - side, is carried to the camera, exposed, and brought back to the dark - room for development