Formalin Hardener SH-1

Supplementary hardener

Sodium Carbonate (monohydrate*)6g
Water to make1000ml
Mixing Instructions: Add chemicals in specified sequence.
Dilution: Use undiluted.
Usage: Ideal for hardening soft emulsions prior to reduction or intensification. Immerse negative for 3 mins, then rinse and immediately re-fix the negative for 5 mins in fresh fixer. Wash thoroughly prior to use of reducer or intensifier.


Formalin is a 40% formaldehyde solution.

*multiply amount by 0.833 if using Sodium Carbonate in anhydrous form.
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