Fum′ing-box.
(Photography.) In printing photographically, the sensitive paper, having chloride and nitrate of silver upon its surface, is exposed to the fumes of ammonia immediately before its exposure to light under the negative; the object being to secure greater depth and brilliancy in the resulting print. The apparatus for this purpose is simply a tight box, in which the sensitive sheets can hang, leaving a space below them for a flat basin containing ammonia. Boxes of this kind are variously constructed, the object in all cases being to admit of the ready introduction and removal of the sheets, as well as of the vessel containing ammonia, without subjecting the operator to unnecessary annoyance from the fumes.