Re: conservation of albumen
Hi Alberto, see this: "...The albumen solution will remain useful for several weeks after the one-week aging period. The smell of the albumen and its color, sedimentation, etc., will reveal when it has decomposed too badly to use..." (from http://albumen.stanford.edu/library/monographs/reilly/chap4.html) Also in the same page (located slightly above the first quotation): "...Beating the albumen is necessary to accomplish the task of chemically breaking down the different protein substances until a more or less uniform substance is created. While beating to a froth does the major work of evening out the viscosity of albumen's different components, further 'denaturation' by chemical means must take place before the albumen is ready to apply to the paper. The chlorides added are vital to the formation of the photographic image, but they also help to denature the albumen; one of the effects of adding chlorides is to reduce the volume of froth produced during the beating step. The third kind of denaturing treatment usually employed is the adjustment of pH by the addition of acids or alcohol. The chemical forces which bind together the enormous molecules of protein grow weaker as the pH is lowered, and the physical properties of the substance change as a result. The effect of adding chlorides and acids, such as acetic acid, and finally beating the egg white is to completely and irreversibly change it. After settling for 24 hours and aging in a refrigerator for one week it is a yellowish homogeneous liquid with a slight 'aged' odor that signals its readiness for use..." So, there's no other information about denaturation and long term storage of albumen solution (as I can see/find) in the monograph. Why not mixing in batches, just enough to coat the needed amount of sheets? (Like say... 40 11x16" - quarter size - sheets at a time.) Albumenized papers can be stored for much longer than a year... Regards, Loris. 18 Ocak 2009, Pazar, 10:34 pm tarihinde, Alberto Novo yazmış: > What do you suggest for the long-term conservation of albumen solution > (say > at least one year)? > Adding a preservative (thymol, sodium azide, ...)? Simple storage in a > sealed jar? Sealed and refrigerated at 4°C? Freezing? > > Alberto
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