Sensitometric Study of Io-bromized Daguerreotype Plates

This research deals with a study of speed and contrast of daguerreotype plates that receive varying levels of sensitizing to the fumes of iodine, then bromine, and finally, a second iodizing. This sensitizing operation along with mercury development and gold gilding are characteristic of the process in its most improved state. Statistical analysis reveals how iodizing and bromizing affect speed and contrast. A field study was conducted to relate the sensitometric data to images produced in the camera. The experiment suggests an exposure index of .05 for the optimum in speed. This would correspond to an exposure of roughly 1 second at f/4.5 on a bright, sunny day