The plate at this stage should look like a clean, good negative, and when viewed by transmitted light the dark parts should not appear absolutely opaque. If laid down on a sheet of white paper there should be no quite transparent portions, unless we except the edges of the plate which were not exposed to light.
The plate must now be washed for twenty minutes in running water, or if that is impossible, in five or six changes of water. Then wipe over the gelatine surface with a piece of cotton wool or the ball of the finger to remove any sediment from the water, give a final rinse, and dry in a good current of air. Drying may be accelerated by blotting the surface of the plate with a clean handkerchief, so that all superfluous water is removed.
Tank and time development has greatly grown in favour during the last few years, and, generally speaking, a higher average of negative is obtained by using a constant developer at a constant temperature for a specified time than by any tinkering in the dark-room. The system is based upon the time necessary to get a good negative from a properly exposed plate or film, and works admirably in practice. An under-exposed plate or film is of no use at any time and if much under-exposed the best plan is to let it go into the dustbin. In cases of over-exposure it is necessary to develop just as long as we should a correct exposure. If we stop development at an earlier stage we shall only get a thin, flat, foggy-looking negative which would not give a decent print in any process.
The expert who has cases of known over-exposure or underexposure to deal with, can, perhaps, modify them to some extent, by in the first instance, using a strong and highly restrained developer, and in the second case by using a weak developer, or at least weak in the essential elements of pyro or other silver reducing salt. This is the reverse practice of the inexperienced, who fancy that over-exposure requires a weak developer and so use a compound that tends to accentuate the flatness of the result.
For tank development the following Kodak formula is very satisfactory :-
Pyrogallic Acid Stock Solution.
Pyrogallic acid ....................
Soda Stock Solution.
Sulphite of soda (cryst.) ............
Carbonate of soda (cryst)......
Water ........................ to
For development take 1 1/2 ounces of each of these solutions and make up to 20 ounces with water. Time of development is 10 minutes at temperature of 65°F.
Watkins' Thermometer Solution.
20 minims Sinclair No. 1 Pyro Solution. 100 minims Sinclair No. 2 Pyro Solution, made up to 1 ounce with water and 5 minims 10% Brom. Pot. added.
This is same composition as Watkins' Thermo Soda.
DEFECTS AND THEIR CAUSES.
Foggy and Thin-looking Negatives. We are constantly shown negatives thin and flat-looking with general fog all over, and complaints are made that the plates must be defective. Generally speaking, defect is due to under-exposure. In such cases, particularly with rapid plates, the developer must do some work, and it consequently reduces silver all over the plate, causing the general fog. A rapid plate that has not been exposed to light will darken when placed in an active developer. We, of course, assume the dark-room light is reliable.
Hard and Brilliant Negatives. Although so different in characteristics from the sort of negatives described above, the cause is generally (he same - under-exposure - but in this case the plate has probably been a slow one. To minimise the " soot and whitewash " trouble with plates prone to give it, reduce the " pyro " or the silver-reducing salt in the developer. Generally speaking, with proprietary developers, use less of the No. 1 or " A " solution, as this invariably contains the active agent, the " No. 2 " or " B " being the accelerator.
Black Specks or Comet Light Markings in Negatives. These are usually caused by metallic particles in the water and are noticed when the plate is taken from the washing tank. They can be quickly removed by inserting the still wet plate in a solution of alum and hydrochloric acid.
When the spots are entirely removed wash again for five minutes, wipe the surface with cotton wool, give a final rinse under the tap and set to dry.
To Remove Yellow Stain from Pyro-stained Negatives. In the case of negatives being developed with insufficient sulphite in the developer or with an old pyro developer, they get very badly stained. The most effective stain remover is Leucogene, a chemical compound prepared by Messrs. Lumidre.
The Canadian Arch For The Coronation Of King Edward VII.
Jas. A. Sinclair,
Hand Camera picture taken with the Sinclair "Una."