Kodak SH-1 Formalin Hardener for Films and Plates
Water - 16 fl. oz. - 500mL - 20 fl. oz.
Formalin (40% Formaldehyde solution) - 2 1/2 fl. dr. - 9.75mL - 3 1/8 fl. dr.
Sodium Carbonate - 73 grains - 5g - 87 1/2 grains
Water to make - 32 U.S. fl. oz. - 1L - 40 Imp. fl. oz.
U.S. Customary units given are exact. Metric measures are accurate to within 250ÁL or 250 mg. Imperial units accurate to within 1/4 gn., 1/8 fl. dr.
NOTE: SINCE THIS FORMULA WAS PUBLISHED, FORMALDEHYDE HAS BEEN CLASSIFIED AS A PROBABLE CARCINOGEN, AND EXTREME CARE SHOULD BE EXCERCISED IN ITS USE.
Hardening prevents excessive softening of the emulsion. It also prevents the emulsion from slipping off the film base and reduces the possibilities of reticulation. The hardener prevents an increase in film "grain."
This hardener is recommended for the treatment of negatives which would normally be softened considerably by a chemical treatment. It prevents excessive swelling of the emulsion and should be used before reducing or intensifying a negative. Immerse the film in this solution for about 5 minutes, and rinse it well before further treatment.