File:The American annual of photography (1912) (14765737775).jpg

Identifier: americanannualof1912newy (find matches)
Title: The American annual of photography
Year: 1912 (1910s)
Authors:
Subjects: Photography
Publisher: New York : Tennant and Ward
Contributing Library: Harold B. Lee Library
Digitizing Sponsor: Brigham Young University

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of the most valuable photographic processes that hehas ever encountered.Stock solutions: (I) Oxalic acid i6 gr. Ferric oxalate 240 gr. Distilled water—hot 16 dr. Oxalic acid 16 gr. (II) Ferric oxalate 240 gr. Potassium chlorate 4 gr- Distilled water—hot 16 dr. (Ill) Potassium Chloroplatinite 219 gr. (=^ oz.) Distilled water 19 dr. Sensitizing solutions: (i) For very soft prints— I 22 mm. Ill 28 mm. (2) I 18 mm. II 4 mm. Ill 28 mm. (3) About same degree of contrast as a silver print. I 14 mm. II : 8 mm. Ill 28 mm. (4) I .10 mm. II 12 mm. Ill 28 mm. (5) For extreme contrast. II 22 mm. Ill 28 mm. It will be observed that these formulae are arranged in theorder of resultant contrast. The quantities given are aboutright for a 9 x 11-inch sheet of ordinary paper, the verysmooth vellums and linen papers requiring slightly less, therough Whatman and charcoal papers from 10 per cent, to 25per cent. more. The quantity used is, of course, directly pro-portional to the area of the paper. 48
Text Appearing After Image:
< SENSITIZING. Cut the paper about one inch larger each way than thefinished print is to be, pin it firmly on a smooth board witha sheet of paper under that which is to be sensitized, measureout the required quantity (the writer pours from each bottleinto a minim graduate and mixes the solutions by pouring backand forth between two graduates), then pour in a pool on thepaper and spread thoroughly, using a flat rubber-set camel-hair, fitch or sable brush. Work the solution back and forthuntil the paper is well covered, and the solution has begun to gointo the pores, then lay aside until surface-dry and completethe drying over a stove or gas-jet. When the paper is bone-dry put it into an empty platinum tin, with preservative, untilready for use. All of these operations may be conducted by thelight of an ordinary window, avoiding direct sunlight. Itis advised to wet the brush and shake it out thoroughly beforebeginning to coat, as it will then absorb less of the sensitizingmixture. Af

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