ORIGINAL FERRIC NITRATE FORMULA

20 g  Glycerol
500 ml Deionized Water
500 ml Isopropyl Alcohol
300 mg Phenosafranine
150 g  Ferric Nitrate
33 g  Potassium Bromide
 One litre water

Dilute 1 to 4 with water before use.

Bleaching time: One and a half times the time it takes to clear.

Temperature:  20C              Agitation:  Intermittent

For rehalogenation after fixing.  Hans Bjelkhagen prefers this over the simpler GP 431 formulation for pulsed masters developed in Neofin Blau diluted 1:1.

Shelf life: This stock solution lasts indefinitely, working solution about one week.

Source: N. J. Phillips and D. Porter, "An Advance in the Processing of Holograms,"  Journal of Physics E: Scientific Instruments 9, 631 (1976).