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Photo Engineer
11-02-2006, 09:39 AM
I have been getting questions about the stability of home made emulsions and home made coatings so here are a few answers to help out.

First, you have to understand that I don't make liters of emulsion or dozens of coatings, so keeping is a rather rare event for me. I usually use what I make rather quickly but....

I have had a busy schedule, so I had some Azo type emulsion in the fridge since April. I coated and tested the stuff last week and it proved identical to the day it was made, so the raw emulsion with no addenda will keep at least 6 months if refrigerated.

I had some Kodabromide/Brovira type coatings that were 9 months old sitting on the shelf here, so I ran those at the same time as the above. Again, the coatings were identical to the day they were made Feb.

Previous results indicate a small speed loss in the Azo type paper when kept on the shelf, but I'm going to re-run those tests. The curve shape and fog did not change, but it appeared that the speed had dropped. Now, I'm not sure, so I'm going to retest that. I coated that last night.

PE