Just looking quickly at some emulsion formulae it is perhaps worth clarifying a few points which confirm what Ron is saying.
In some commercial Bromide paper emulsions the ratio of Potassium Bromide to Potassium Iodide can typically be around 60 KBr :1 KI (by weight), with faster emulsions the amount of Iodide is often higher 40:1 is fairly typical.
Potassium Iodide is also used in Azo type emulsions as Ron has indicated, and the formulae have been published, in this instance the ratio of Sodium Chloride to Potassiun Iodide is around 130-220 NaCl: 1 KI by weight
Of course not all emulsion formulae contain Potassium iodide and many used to contain Cadmium Chloride, and occasionally Lead Nitrate, but one thing is for certain the Agfa Lupex - Azo type formulae does contains KI.
Some of the other formulae will be posted here on APUG as soon as the Article section is finally revamped.
Ian
Last edited by Ian Grant; 10-13-2007 at 06:36 AM.
Reason: Add NaCl:KI ratio
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