[Alt-photo] Re: casein and Ferrari red

[Christina Anderson]

Dear All,

So glad all of you use that color with no problem!!

Here's a picture of the coagulation just in case you think I'm nuts :) I've also put at the same place my latest "two best friends" for colloid printing.

http://christinaanderson.visualserver.com/Text_page.cfm?pID=1953

After I made the post, I continued casein printing and an hour later when I looked at the mix the curdle had subsided into a usable solution!  It was smooth again in other words. So now I was really puzzled.

I even tested it in a print and it worked fine. So thank heavens PR254 is still fine. 

So I went and got a tube of PR254 and then my stock solution (PR254 mixed in gum arabic which I had used) and tried both. The PR254 tube worked fine enough, with a slight thickening. The stock solution (1 tube of PR254 mixed in 45ml gum arabic) immediately curdled the casein. 

So I took my Daniel Smith gum from the gallon container and mixed it into the casein and immediate curdle.

I then tested gum arabic against water to see if it was added liquid and the water did not curdle it.

Thus I have ascertained that gum in tandem with my casein solution is most likely the issue (it was 1/4 tsp of gum/pigment in 1 T casein), but I have never seen this happen before with all the layers I have done, since I started mixing up casein/pigment at time of use. I have to mix a new batch of casein today so I can mix fresh with the gum again and ascertain if the age of the casein is an issue, too.

Marek, the nickel azo yellow working strength solution (I mixed 500ml of it, like I usually do gum arabic and the gum/pigment solutions last forever) precipitated hard chunks after 1 or 2 weeks. They were not usable. Hard curds, not soft curds like yesterday. But I have always used this pigment at time of use. I mix a tube of it in 45ml water to dilute it (it is SO strong) and then I use 1/4 tsp of that to 1 tsp-1T casein. It's just such a concentrated pigment I have a hard time measuring out the right "pea" size, but that's just me.

My casein doesn't go bad, because I use either thymol or now sodium benzoate (1/4 tsp per 100ml solution) as a preservative. In the past, it would start thickish and then get watery over a period of time. Once I did not preserve it and left it in a warm car. Stupid me. What a smell. I threw all away, 250ml bottles and solution. 

Marek, you say you don't use your casein for a couple weeks after mixing. How come? I literally mix 'n go.

Guido, so glad to hear from you!! You haven't posted in a long time! You might not know that you are quoted in my book! I was so surprised at your short exposures (20-30 seconds) when I first read them on an alt post you made years ago, but actually, this whole last period of time I have been exposing all layers at 45 seconds. Incredibly fast.
Chris



Christina Z. Anderson
christinaZanderson.com

On May 14, 2013, at 8:03 AM, Guido Ceuppens wrote:

> Christina,
> I have used casein with powder pigments and acrylic paints but never with
> aquarelle paints. I never saw the curdle or coagulation of the casein as
> you described. I have always used powder casein (different
> manufacturers/sources,
> but now Kremers) made up with ammonium carbonate, borax and lately simple
> household ammonia. I keep the casein mixture for not longer than about 3
> days (it's so easy to mix) and the mix of pigment/paint, casein and
> dichromate for about 24 hours.
> 
> Guido
> 
> 
> 2013/5/14 Marek Matusz <marekmatusz at hotmail.com>
> 
>> Kees,
>> 
>> I use same type of casein mixed from powder and ammonium carbonate with a
>> fair amount of preservative.
>> 
>> Marek
>> 
>> 
>>> From: workshops at polychrome.nl
>>> Date: Tue, 14 May 2013 13:46:17 +0200
>>> To: alt-photo-process-list at lists.altphotolist.org
>>> Subject: [Alt-photo] Re: casein and Ferrari red
>>> 
>>> Hi Chris,
>>> 
>>> Tried Kremer XSL irgazin red PR 254 (powder igment) in casein. No
>> problems!
>>> My casein mix is from casein powder with ammoniumcarbonate.
>>> 
>>> Kees
>>> 
>>> 
>>> 
>>> 
>>> On 13 mei 2013, at 18:30, Christina Anderson <
>> christinazanderson at gmail.com> wrote:
>>> 
>>>> Dear All,
>>>> I have been working on a body of casein prints. Today I decided to use
>> some PR254, that beautiful Ferrari Red (Daniel Smith Pyrrol Red, Da Vinci
>> Red, Maimeri Sandal Red, M.Graham pyrrol red, Rembrandt permanent red deep,
>> Schmincke scarlet, Sennelier red, Winsor red are some brand names). Works
>> great with gum for a brilliant lipstick red.
>>>> 
>>>> I mixed it up with my casein and it was instant curdle/coagulation of
>> the casein! No problem at all with the usual colors, but with the metal
>> salts as has been discussed on the list you can work with them but stock
>> solutions will lump up in a brief time into insoluble chunks so I never mix
>> stock casein anymore once I learned that lesson. However, with nickel azo
>> yellow, for instance, one of my favorite yellows that lumps up, I can still
>> use it if I mix it up right at time of use. Same with red iron oxide.
>>>> 
>>>> But PR 254 is diketo pyrrollo-pyrole. Don't have any idea why that
>> would make this happen instantly. Does anyone have a guess why this pigment
>> causes instant coaglulation and precipitation of the casein??? Is it just
>> an acidity thing or is it a metallic salt? It precipitated the casein into
>> squishy curds. Never seen this happen so rapidly before...
>>>> 
>>>> Any other casein printers experience colors that coagulate, or want to
>> pull out their PR254 and see this happen? If you have, what colors?
>>>> Chris
>>>> 
>>>> 
>>>> Christina Z. Anderson
>>>> christinaZanderson.com
>>>> 
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