Storing Liquid Emulsion
I'm a grad student currently making dry plates using (our good friend and fellow Oregonians) Rockaloid Liquid Light. My advisors husband (also fellow Photographer/Tech Nerd) gave me the AJ-12 Doc today and I'm very much interested in making my own emulsion. My question is - the AJ-12 doc talks about coating plates and storing them until use, is it possible to store the emulsion in a light tight bottle and keep refrigerated/at room temperature and reheat when needed a'la Liquid Light?
Any thoughts on this?
I've looked through the forums here and haven't found a real good definitive answer. Hope you all can help! Thanks in advance!
It should keep well if refrigerated (NOT frozen). The "washed" emulsion is fairly stable, the "unwashed" emulsion is very stable (I had some in my fridge for months and it was fine).
Adding a few drops of 10% thymol in ethanol/IPA will lessen the chance of any mold growth. It's best to re-melt only what you can coat in a session - repeated re-melting will likely cause unwanted ripening and/or damage the gelatin. If you're using a hardener, add it only to what you are immediately coating.
TOO COOL another plater !
Wonderful!! Thank you for the information. I swear...with the cost of making vs. buying the rockland stuff, I'm a little bummed I didn't find this recipe sooner!! :D Thanks again!
When I last used liquid emulsion, I found I only needed a small amount at one time and donít like the idea of reheating the whole bottle again and again to tap some off. So I heated it and then decanted the whole bottle into cassette tubs and stored them in a black plastic paper bag. In this way I could heat up only a small quantity at a time, as needed and none of the emulsion got heated more than twice. Perhaps this was unnecessary, I donít know.
I have kept Liquid Light in the refrigerator for a couple of years and it still seem to work fine. I froze my first bottle (before I read all the instructions), and it still seemed fine. I never did freeze it again though. I think the idea of putting it in smaller containers is good. I would think repeated heating would shorten the life.
heating and reheating and reheating does break down the emulsion .. i use liquid light &c and
squeeze a blob out of the bottle so i don't reheat the whole thing, just the blob .. if i need more i squeeze more out
and if it is too much i put it in some a film canister ... i love using expired liquid light
it has higher speed and more contrast than usual, or so it seems ...
Light tight wide mouth jars can be purchased on-line or via phone or mail from a huge number of companies. I keep 50ml, 100ml, 250ml and 500 ml jars here to divvy up my emulsions as needed. I have kept them this way for a year or more, but Ian says it best above. Just dont re-heat the stuff or it changes speed, curve shape and fog level.
I have another question. I was in the darkroom today and noticed that one of my two bottles of AJ-12, one that hasn't been warmed up at all since it was made around 11/15 had turned to liquid at room temperature. It wasn't a gel anymore. I put it in the fridge before I left, but I'm assuming that this is a sign that the gelatin has broken down and that the emulsion is a goner. Does anyone know if that's a correct assumption?
Also - if AJ-12 doesn't hold up at room temp for more than a few weeks, instead of making batches of emulsion every couple of weeks, are there any basic chemistry changes/additives that I can make that could help lengthen it's shelf life? Would using photo grade gelatin help at all?
Any input is greatly appreciated as always!
Emulsions should never be stored at room temperature. All of them go bad with time.
Use about 5 drops of 10% Thymol in pure alcohol (not denatured) in every 200 ml of emulsion. Mine keep for a year or so in the fridge this way. Of course, washing accelerates the deterioration if the wash water is "buggy".