[alt-photo] Re: Casein source

[Christina Anderson]

Alberto,
When you say "last a week" do you mean it was no longer usable or just stunk? Did it no longer respond to dichromate hardening and UV light? 
It calls to mind how they used to let gum sour so it was quicker acting, back in the late 1800s.
My ammonium caseinate was ready to use essentially within a couple hours. There is no smell whatsoever, except for a slight milk odor. Very user friendly. Sodium less so. 24 hours later my sodium caseinate is like a very concentrated rubbery gelatin solution that I would have to liquify before use. I have absolutely no idea why the big difference between the two forms of casein. Maybe you can clarify? 
I am not interested in a process using ammonia fumes, really just looking for one that is whip 'n' go. The quicker and easier the better it is for students (and me), hence a little bottle of liquid casein or a jar of powdered casein would be just so...convenient.
Christina Z. Anderson
christinaZanderson.com

On Apr 12, 2011, at 8:33 AM, Alberto Novo wrote:

> Chris, 
>> ... I was able to get samples of sodium and ammonium which I mixed with no added alkali. I wanted to compare apples to apples in the mixing. Ammonium does get thinner after a few days and I am waiting to see if sodium does, too.
> 
> The alkalies break the bonds among carboxylic and amino group of the casein, which is a protein. The stronger the alkaly, the faster should be this effect.
> When I prepared my mix from casein and ammonia, I found that it would last about a week in a tightly sealed jar in my refrigerator. However, as I have already told, such a mix can be ready for use in less about half an hour. 
> Alberto 
> www.grupponamias.com
> www.alternativephotography.com/wp/photographers/rodolfo-namias-group 
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