Hardening bath for plates, films and papers. For use after fixing.

IngredientQuantity
Mix chemicals in order.
Formalin 40%50
mililiters
Water to make1liter

Immerse for between 10 and 20 minutes.

This hardening bath is especially recommended when a negative is to be subjected to various chemical treatments such as reduction, intensification etc. It is also useful in tropical climates as traces of formalin inhibit the growth of mould and bacteria.

Warning: Formalin, a 40% solution of formaldehyde in water, is a powerful taning agent and acts upon the skin and, if allowed to be smelled, also upon the mucous membranes of the nose.