Development and Developers
method will allow considerable latitude in the time of exposure. Several plates may be developed in the same solution, but the developer gradually loses its energy and will not keep long after being mixed.
Fixing. Hyposulphite of soda ... ... ... ... I ozs.
Water ... ... ............ 16 ..
Pour sufficient of the above, when dissolved, into a porcelain dish and immerse the developed and washed plate for 2 or 3 minutes, or until fixed, then rinse thoroughly under the tap and apply the following : -
Sulphuric acid ... ... ... ... ... oz.
Saturated solution of alum ... ... ... 20 ozs.
Pour a small quantity of the above repeatedly over the plate for about half a minute, or until the slight deposit of oxalate of lime (caused by the washing water) is dissolved away, and the picture becomes bright and clear. The high lights of the transparency should be perfectly bare glass without a trace of deposit of any kind ; as soon as cleared wash well in repeated changes of water, and allowed to dry spontaneously.
Caution. Great care must be taken that not the faintest trace of hyposulphite of soda comes into contact with the developing solution or with the plate before or during development. Separate dishes must be used for each solution. The dishes, as well as the hands of the operator, should be frequently washed and kept scrupulously clean during the various mani-pulations, otherwise the films are liable to become stained and discoloured. When quite dry the transparencies may be varnished with good clear negative varnish applied with heat in the usual way.
Bromide Opals. - Instructions for Use. Exposure. Place the opal plate film-side next to the negative in an ordinary printing frame, and expose to the light of a paraffin lamp, or by preference, that of an ordinary fish-tail gasburner, at a distance of 2 feet from the flame, for from 12 to 24 seconds, according to the density of the negative.
Development. The following formula will be found to give very satisfactory results.