The DARKROOM COOKBOOK, Third Edition

268 THE DARKROOM COOKBOOK
FORMULA #121
Kodak SB-5
Non-swelling acid rinse bath.
Water, 500.0 ml
Acetic acid, 28% solution, 32.0 ml
Sodium sulfate, anhydrous, 45.0 ml
Water to make 1.0 liter
This bath is satisfactory up to 80F/27C. It should be replaced after processing about
12 rolls per liter. The bath should not be revived with acid.
When working at temperatures below 75F/24C the life of the acid rinse bath may be
extended by giving fi lms a few seconds rinse in running water prior to immersion in the acid
rinse.
FORMULA #122
Kodak SB-8
Citric acid odorless stop bath.
John Wimberley: For decades the standard ingredient of stop baths has been acetic acid,
which has one serious problem; its odor is strong and corrosive to mucous membranes, making
long term exposure in the darkroom problematical. Citric acid is a much healthier alternative
because it is essentially odorless.
Water, 750.0 ml
Citric Acid, 15.0 g
Water to make 1.0 liter
FIXERS
● Crystalline hypo, when mixed with water, produces a noticeable lowering of temperature.
Always begin with water of at least 90F/32C when mixing the crystalline form.
● Use 64% of the anhydrous salt as a substitute for the crystalline form. With either crystalline or
anhydrous, mix the hypo fi rst then add the remaining ingredients.
● Dissolve the acid ingredients separately (e.g., boric acid) in a small volume of hot water, especially
when a mixture of sodium sulfi te and acetic acid is used.
● Removing the hardener from fi xer will improve the gloss on paper.
● As a very general guideline, most fi xing baths, rapid or standard, have a capacity of twenty
8 � 10 inch prints or fi lms per liter. If no capacity is specifi ed, use this as your guide for archival
processing of fi lm and paper.
● When called for use boric acid, granular, as powdered boric acid is extremely diffi cult to dissolve
in water. Boric acid is used as cockroach poison. Do not ingest.
● Excessive fi xing times will promote adsorption or retention of the fi xer complexes in gelatin, or
more particularly on the fi bers of paper base, and should be avoided. In addition, excessive fi xing
can bleach silver images, especially those on paper prints. Warm-tone images are particularly at risk.