The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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Development and Developers
the loss of light. A convenient method of printing by artificial light consists in burning an inch or two of magnesium ribbon at a distance of 12 inches from the printing frame. These plates can also be used for making enlarged or reduced positives from negatives in the camera, but for this purpose a much longer exposure, probably 5 to 10 minutes, in a good light will be found necessary to ensure success.
Make two stock solutions as follows : -
No. 1.
Neutral oxalate of potash Chloride of ammonium Distilled water ...
No. 2. Sulphate of iron Citric acid
Alum .................
Distilled water ... ... ... ...
2 OZS.
40 grs.
20 OZS.
4 drms,
2 ..
2 ..
20 OZS.
The above solutions will keep indefinitely. When required for use mix -equal portions of the above solutions, adding No. 2 to No. 1 to form the developer, place the exposed plate film uppermost in a porcelain dish, and pour over rapidly and evenly the mixed developer, rock the dish during the progress of development (which may be examined from time to time by yellow or non-actinic light), when sufficient density is obtained, which will usually be in about 2 minutes, pour off the developer into a measure, and flood the plate with water and wash well under the tap. The above developer with moderate exposure will give positives of a warm black colour, still warmer tone may be easily obtained by simply diluting the mixed solutions with an equal quantity of distilled water, or by adding to each ounce 2 or 3 drops of a 20-grain solution of bromide of potassium, and proportionally increasing the time of exposure. Short exposure and rapid development will give black tones, while full exposure and slow development will give warm brown or red tones to the transparency. It will be found a good plan to make up two separate portions of developer, strong and weak, and commence with the latter ; should the plate prove to be under-exposed the developer must be poured off, and the more concentrated solution used to bring out the picture and complete development. This