Hardening fixer, formula

For tray processing of paper it is not necessary to use hardener unless you habitually experience scratches on the print emulsion from handling. If scratches do occur, hardener should be added to the fixer. Start by adding one-third of the manufacturer s recommended amount and increase in one-third increments until the problem is eliminated For example, if the directions call for 45.0 ml of hardener, start with 15.0 ml if the problem persists, add another 15.0ml. It will be necessary to neutralize or wash out the hardener prior to most toning processes (Formulas Miscellaneous De-hardener). 

If a fixer with hardener has been used re-fix in Plain Hypo (Formulas Fixers Plain Hypo) or use Dehardener (Formulas Miscellaneous Dehardener) before toning. 

F-5 is the standard sodium-thiosulfate-based formula. Many commercially marketed fixers are essentially unaltered versions of this formula. Use this formula for film and paper when hardening is desired. 

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