![Heico Perma Wash (Liquid) for Black & White Film & Paper - 1 Quart Heico Perma Wash (Liquid) for Black & White Film & Paper - 1 Quart](https://cdn11.bigcommerce.com/s-f9fok/images/stencil/370x488/products/35450/63873/31QUR5WoMTL__69100.1640287590.jpg?c=2)
Heico Hardener Part B for NH-5 Fixer is for the photographer who wishes to regulate the hardener himself should use NH-5 with this hardener.
A hardener is sometimes used in the fixing of film, in order to "harden the emulsion to the base of the film".