783. Pyrocatechin Solution

Pyrocatechin Solution. A one-solution, quick-acting developer, giving black tones.

Boiled or distilled water.......

5 ounces


120 grains

Bromide of Potash.............

,............ 8 grains

Sulphite of Soda...............

1 ounce

Caustic soda (in sticks).........

60 grains

Dissolve each ingredient in the order named.

For Use, Take: One dram of this stock solution to each ounce of water.

784. Eikonogen - Hydroquinone Developer: - Warmei-tones.

No. 1

Pure water

.......... 15 ounces

Sulphite of Soda

.......... 6 drams

citric Acid

........... 15 grains


.......... 90 grains


45 grains

No. 2

Pure water

.......... 10 ounces

Caustic soda (in sticks)

.......... 60 grains

Bromide of Potash

60 grains

For Use, Take:

Solution No.1

........... 2 ounces

Solution No.2

1 ounce

785. The fixing bath must be fresh and clean. Use about six (6) ounces hypo to the pint of water, or use our acid chrome-alum fixing bath.

786. The plate must be thoroughly fixed and thoroughly washed. When the last trace of silver bromide disappears, consider the plate only half fixed.

787. It is advisable (after washing well) to use a clearing solution, even if there is no stain apparent.

788. The plate must be well washed before putting it into the clearing solution.

789. The tone of a lantern slide made on these plates may be decided either by the length of exposure and the development, or by an after - process.

790. The rule of development toning is that prolonged exposure and a heavily restrained developer give warm tones. The restrainer generally used is a ten-per-cent. potassium bromide solution.

791. Hydroquinone Developer

Hydroquinone Developer. (For black tones.)

English Weights and Measures.

Metric Weights and Measures.

20 ounces Distilled water...........

or 1000 c. c.

60 grains of Hydroquinone

or 7 grammes

2 ounces Sulphite of Soda (cryst.) . .

or 100 grammes

6 ounces Carbonate of Soda (cryst.) .

.or 300 grammes

40 grains Bromide of Potash.......

or 4.6 grammes

(Use without diluting.)

Dissolve the hydroquinone in the water and add the other chemicals in the order given.

792. If the plate is properly timed, development will be complete in about two minutes. This developer can be used for several plates by adding a little fresh developer to that used after each development.

793. Some lantern slide experts prefer to slightly overdevelop, and then after fixing and washing to reduce the slide to the proper density; this method produces very crisp, clear slides. Those wishing to try this method should use our Howard Farmer reducer. This reduction can be done by daylight. Wash well after reducing and rinse in absolutely clean water before setting up to dry.