Having coated a plate with the common negative collodion and excited
it in the usual nitrate of silver negative bath, expose it to the
light for about a second at the door of the dark room, wash it and
then apply to the surface as a wash a solution of
Iodide of potassium 16 grains.
Bromide of potassium 8 "
Water 1 ounce.
The plate is now ready for exposure in the enlarging camera; the
lime or the magnesium light being sufficiently powerful for the
purpose. On its removal from the camera the plate is washed,
immersed for a brief period in the nitrate of silver bath, or
otherwise treated with a solution of this salt, after which the
image is developed by the ordinary developing solution [p207] for
wet plates. In this way is obtained an enlarged negative from a
small one without the necessity of an intermediary transparency.