Home made emulsion and coating stability

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by Photo Engineer, Nov 2, 2006.

  1. Photo Engineer

    Photo Engineer Subscriber

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    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