[alt-photo] Re: casein

[Alberto Novo]

Hi Chris, 

about making homemade casein, I tried this some years ago when I began 
experimenting casein printing.
My first approach had been preparing casein from powdered milk, finding a 
dry casein yield of 23% by weight. I don't know if changing powdered milk 
the yield may be different.
 From the yield, I calculated that Franklin Enos/Ernest Theisen recipe is 
equivalento to about 5% solution of casein, while Bob Schramm 
(www.usask.ca/lists/alt-photo-process/alt95/0831.html if still there...) 
cited by Laura Blacklow in Alternativephotography.com is 4%, and that in 
"Spirit of Salts" is 10%.
In Italy we have not cottage cheese and use ricotta instead. But ricotta is 
not casein, being made warming the whey up to 90°C, and lightly acidifying 
it (ricotta means "cooked two times") so that albumin and globulin 
denaturate and become insoluble. So, I did not investigate about a potential 
"ricotta printing" :-)
For me, powdered milk was not easy to buy, and fresh low-fat industrial 
cheese (a possible substitute of cottage cheese) are often treated with 
lactic or citric acid, alginate and cream. Finally I ended using dry casein 
in order to avoid all my problems of supplying and purity. 

BTW, I am still without my darkroom, so that I have not yet had the 
opportunity to give a try to your ammonium caseinate. 

Alberto
www.grupponamias.com
www.alternativephotography.com/wp/photographers/rodolfo-namias-group