413. Although there is no developing agent that can equal pyro for the best general results, yet some object to its use owing to it staining the ringers when proper care is not exercised.

414. While either, metol or hydroquinone make a good developing agent, yet metol to some users is poisonous, and therefore, undesirable; consequently, the best developer that will not stain the fingers, and is not poisonous, is hydroquinone and eikonogen.

415. This developer can be altered to produce most any desired results; while it does not produce the printing quality in the negative that pyro does, yet it serves as the nearest developing agent to pyro that is practical for all developing purposes, with the least objection.

416. This developer can be used repeatedly for several batches of plates, but for the best results should be made up fresh for each day's work. It is desirable to save the developer of one day's use for the developing of plates you believe to be over-exposed slightly, and after starting the plate in normal developer, and you found it to be over-exposed, transfer to the tray containing the old developer, and allow it to remain in this solution until it takes on sufficient strength, then transfer to the normal developer for final developing. You will find that plates developed with this developer prepared exactly according to formula will have a very fine grain, and the color will be very near that of a pyro developed negative. The shadows and highlights will be clear and with good detail.

Formula for hydroquinone and eikonogen developer: -

Stock Solution, No. I

Hydroquinine

40 grains

Eikonogen..................

............. 120 grains

Sulphite of Soda (Anhydrous)

1 ounce

Citric Acid................

............. 20 grains

Water......................

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

Stock Solution, No. 2

Bromide of Potassium.........

............ 5 grains

Carbonate of Soda (Anhydrous)

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

Caustic Soda (Sodium Hydrate)

30 grains

Water.........................

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

(If crystals sulphite or carbonate are used, use double the quantity.) Mix all the chemicals in the order given.

For use take one ounce of each of the stock solutions, and add one ounce of water. This will then give you three ounces of developer, sufficient for the developing of a 4 x 5 plate. If the factorial method is employed for this combination developer the factor would be eight.