The Dictionary Of Photography

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

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Reduction                                           Reduction of Density
Solution I. Chloride of calcium (crystalline) ... ... 147 grs.
Distilled water         ... ... ... ... 2 ozs.
Solution II. Sulphate of copper ... ... ... ... 249 grs.
Distilled water ... ... ... ... 10 drms.
Dissolve each separately, mix, and filter. For obtaining warm tones with bromide paper, the finished print is bleached as above, and then redeveloped with hydroquinone or dilute ferrous citrate developer. To obtain a regular tone it has been recom-mended to bleach Alpha paper with mercuric chloride, and redevelop with ferrous oxalate.
Reduction (in Size). An exceedingly useful operation in the preparation of lantern slides or prints from larger sized negatives. One or two methods may be adopted, both of which are satisfactory - one for daylight, the other for artificial light; and the arrangements suggested for enlarging with some modi-fications will do. The negative to be reduced in size should be placed in the same position (see Enlargement), but in this case the lens is turned towards the negative, and focussed on the ground-glass screen in the usual way. The distance between the negative and the lens may be found by referring to the table given under Enlargement, or the same rules there given may be used for finding the distances, only they must be reversed - that is, whereas in enlargements the greater distance is between lens and sensitive surface, in the case of reduction the greater distance must be between the lens and negative. (See Pigeon Post and Micro-Photography.)
Reduction of Density. When a negative or print has been over-developed or over-printed, the following processes may be adopted for reducing them : -
Reduction of Negatives. Howard Farmer's Reducer. This was suggested by Howard Farmer in 1883. Make a 10 per cent, solution of ferridcyanide of potassium, immerse the negative which should preferably have been dried in a 1:8 solution of hypo, and then add a few drops of the ferridcyanide reducer, and carefully watch the action, taking the negative from the solution before quite reduced to the desired degree. The