The DARKROOM COOKBOOK, Third Edition

308 THE DARKROOM COOKBOOK
SOLUTION B
Distilled water at 68F/20C, 750.0 ml
Sodium bisulfi te, anhydrous 3.8 g
Hydroquinone, 15.0 g
Kodak Photo-Flo 200, undiluted, 3.8 ml
Water to make 1.0 liter
SOLUTION C
Distilled water at 68F/20C, 750.0 ml
Sodium thiosulfate, pentahydrate, 22.5 g
Water to make 1.0 liter
The order of mixing is important and should be followed. To 1 part of Solution A, add with
constant stirring, 2 parts of Solution B. Still stirring, add 2 parts of Solution C, and fi nally 1 part
of Solution A.
To intensify negatives, fi rst wash the negatives to be treated for 5 to 10 minutes. Harden
them for 5 minutes in Kodak SH-1 Formalin Supplementary Hardener and wash them again
for 5 minutes.
The greatest possible degree of intensifi cation is achieved by treating the negatives for
approximately 10 minutes at 68F/20C. If a lesser degree of intensifi cation is desired, treat the
negatives for shorter times. Agitate them frequently during treatment to prevent streaking.
Treat only one negative at a time when processing in a tray.
When a satisfactory degree of intensifi cation is reached, wash the negative for 10 to 20
minutes and dry as usual.
NOTE: The stock solutions will keep in stoppered bottles for several months; the mixed
intensifi er is stable for 2 or 3 hours without use. After using it once, discard the working solution,
as it may leave a silvery scum on subsequent negatives.
Caution: Add the concentrated sulfuric acid slowly with constant stirring to the cold solution
of the bichromate.
PAPER INTENSIFIERS
FORMULA #181
Chromium Intensifi er for Prints
SOLUTION A
*Potassium bichromate, 30.0 g
Water to make 500.0 ml
* Potassium bichromate is an allergen to some people and a suspected carcinogen. See precautions
under potassium bichromate in Pharmacopoeia.
SOLUTION B
Hydrochloric acid, concentrate, 55.0 ml
Water to make 500.0 ml