[alt-photo] Re: casein odd process

[Christina Anderson]

Hmm...well, we've talked before about FAC's ability to crosslink gum and so it must have the same action on casein.

 It is interesting to read the patents that are more to do with a) substituting casein for albumen or collodion on glass plates and b) brushing this mixture on a bromide print already exposed and the metallic salts will make the casein insoluble proportionately. I mean, how ridiculously complicated they made it. But the advantage to their way of thinking was it was (ta da) MATTE and glossy "was disturbing."

Casein was known to be faster and more flexible, and developed more quickly. I find all those true, too.

Casein was also recommended in place of albumen during the war to save on eggs.

Research into it is laborious. Gum was a piece of cake compared to casein. It abounded. It's not enough to look at indexes for "casein/caseine/kaseine" because a first mention will be something like "A new improvement on the collodion process." 

But what I find interesting about the formula, below, is the proportion of casein--6.6%.
Chris



Christina Z. Anderson
christinaZanderson.com

On Aug 31, 2011, at 7:59 AM, Keith Gerling wrote:

> This is very interesting.  I had just assumed that the process you has
> referred to was the one in the Sherer book where casein was used like
> albumen.  This one?  What is it supposed to DO?  Just FAC in an emulsion?  I
> don't get it.  I'm no chemist but I sense something is missing!
> 
> Keith
> 
> On Wed, Aug 31, 2011 at 8:44 AM, Christina Anderson <zphoto at montana.net>wrote:
> 
>> Keith,
>> 
>> Since you asked....
>> 
>> In searching for casein (still) the one formula I came across a patent for:
>> 5g of anhydrous casein, 75 ml water, 2 ml ammonia, and 2.5 g ferric ammonium
>> citrate (FAC). Brushed on paper.
>> 
>> I have found continually that casein cannot be mixed with metallic salts
>> because they will, what is the term, "throw down" and insolubilize. This is
>> one advantage I see in gum is the ability to mix stock pigment solutions
>> with no hardening.
>> Chris
>> 
>> 
>> Christina Z. Anderson
>> christinaZanderson.com
>> 
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