Scientific American Supplement, No. 388, June 9, 1883 by Various
page 66 of 156 (42%)
page 66 of 156 (42%)
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_A.--Oxalate Developer._
Temperature of developer 4-8° C. 16-17° C. 26-28° C. Time of development 1 min. 3° W. 8° W. 13° W. " " 2 min. 9½° W. 10° W. 15° W. _B.--Pyrogallic Developer._ Temperature of developer 1-2° C. 26-28° C. Time of development ¼ min. 6° W. 10° W. " " 3 min. 14° W. 15° W. * * * * * INTENSIFIER FOR WET PLATES. By MAJOR WATERHOUSE. The collodion process is still preferred for reproducing black and white designs, drawings, engravings, etc., where very dense negatives are desirable. The fixed and washed plate is put in a bath of bromide of copper (ten per cent. solution); the film whitens immediately, and when the color is even all over, the plate is taken out and plunged into a bath of the ordinary ferrous oxalate developer. It takes a dark olive tint, which is very non-actinic, the shadows meanwhile remaining very clear.--_Photo. News._ |
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