[alt-photo] Re: casein history

[Christina Anderson]

Has anyone tried this formula, the ferric/casein one? It is the Gateau patent. Kees?

I notice no mention of hydrogen peroxide in the developing bath in this.

My words, below, not a quote of the patent but refers to a discussion in the BJP.

The formula consisted of 5g casein in 75ml water + 2ml ammonia. Into this is added 2.5g ferric ammonium citrate and pigment. The print is exposed as normal. The paper is described as more sensitive with better keeping properties. Its drawback was the need for chemicals in the development water (ammonia, sodium carbonate, potassium oxalate), unlike regular carbon tissue.

Chris

Christina Z. Anderson
christinaZanderson.com

On Jul 10, 2012, at 11:38 AM, Guido Ceuppens wrote:

> I use 1 part casein/paint + 1 part saturated Pot Dichromate. I use
> acrylic colors as well as powdered pigments in a "heavy" mix and do
> not bother about transparency of the colors, I like (at least at this
> moment) very colorful and saturated images, development is sometimes
> carefully but most of the time very vigorously with brush or even
> sponges.
> Guido
> 
> 2012/7/10 Christina Anderson <zphoto at montana.net>:
>> What an easy formula, Guido. I see it is about a 14% solution. Do you combine that equally with dichromate? Are you still using acrylic colors in the mix or powdered pigments?
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