Ewesly / Holographic Formulae / PBQ

Bleach solution

30 g  Potassium Iodide
15 g  Borax
2 g  Potassium Dichromate
2 g p-Benzoquinone added just before use.
One litre water

Processing

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

Temperature:  20C              Agitation:  Intermittent

Shelf life:  Probably not too long after the PBQ is added.

Source: <a href="NickAdvances.PDF" title="The Origins of the Dreaded PBQ" target="_new">N. J. Phillips, A. A. Ward, R. Cullen, D. Porter, "Advances in Holographic Bleaches," Photographic Science and Engineering 24, 120 (1980). </a>