|Sodium Sulfite (anhydrous)||75||g|
|Acetic Acid 28%||235||ml|
|Boric Acid (crystals)||37.5||g|
|Cold water to make||1000||ml|
|Mixing Instructions: Add chemicals in specified sequence. Allow solution to cool after mixing. To make 28% acetic acid from glacial acetic acid, dilute 3 parts of glacial acetic acid with 8 parts water. Use boric acid crystals as specified, do not use powder as it is extremely hard to dissolve.<br><br>A 30% hypo fixer solution is made by dissolving 300g of Sodium Thiosulfate (Hypo) in sufficient hot water to make 1L. Allow to cool.|
|Dilution: Add 1 part hardener to 4 parts 30% hypo fixer solution|
|Usage: Fix film for 10 mins or double the clearing time.|
NotesThis hardener can be added to other commercial acid fixers, but should be tested prior to use on important work. Fixing time will be less with modern rapid fixers; however, hardener will increase fixing times listed on the bottle.