The Dictionary Of Photography

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

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Feer-type
original conditions of solubility and colourlessness. The picture is thus developed. After exposure the print is washed with water or very dilute hydrochloric acid, by which means the un-changed preparation, which has not been exposed under the negative, is removed. The print is then fixed and finished when dry. The following may be taken as samples of solutions : -
I.
Sodium toluene-diazosulphonate...... 25 parts.
............... 25 ..
Sodium hydrate ... ,........ 8 ,,
Water           ...............1000 ..
II.
Sodium ditolyl-tetrazosulphonate ... ... 25 parts.
Metaphenylene-diamine ... ... ... 20 ,,
Water           ...............1000 ..
III.
Sodium ditolyl-tetrazosulphonate... ... 25 parts.
Resorcinol ... ... ... ... ... 12 ,,
Sodium hydrate ...... ... ... 16 ..
Water           ... ••• .........   1000 ,,
The following may also be used : -
IV.
Sodium ditolyl-tetrazosulphonate ... ...      30 parts.
Resorcinol ...... ... ......      20 ..
Sodium hydrate ............      15 ..
Distilled water ............   1000 ..
Finely powder all the salts and dissolve in the water by the aid
of a gentle heat.
V.
Sodium ditolyl-tetrazosulphonate......      30 parts.
a-naphthol ... ... ... ... ...      25 ..
Sodium hydrate ............        7 ..
Distilled water ......... ...   1000 ,,
VI.
Sodium ditolyl-tetrazosulphonate......      30 parts.
Phenylendiamin ... . . ... ...      20 ,,
Distilled water ... ...... ...   1000 ..
3ii