[Alt-photo] Re: casein and Ferrari red

[Marek Matusz]

Chris, It is good to hear from you again, and welcome to the summer break from your school work. Ever since  I had some time to read your chapter on casein I wanted to comment on your pigment choice compatibility with casein. I have been using nickel azo yellow as my yellow for casein and never found any problems with it. Unlike gum printing I do not make casein stock solutions. My casein lasts for about a year and my gum stock solutions last for years (so far about 3-5 years). Since my casein solutions do not last that long I have not been making stock solutions, just mixing pigments on the fly and never had a problem say within 2-8 h of mixing.Your note got my curiosity up and I mixed some PR 254, ferrari red (DS) with my sock casein solution and it mixed just fine. It has been sitting for about an hour now with now issues. I do remember now that I did a project earlier with the use of PR254 for a spot color with no issues as well. I will keep the mix for a few days to see if I can spot any problems. I know that my casein mix is completely different from what you practice. Perhaps some of the components make the difference and even the age of the mix since I do not use it before a week or two after mixing. My current stock casein solution is about 4 moths old. WHat brad of PR254 did you use? That is definitely an interesting topic to pursue further. I will keep you updated on the  PR254 experiment   Marek
 > From: christinazanderson at gmail.com
> Date: Mon, 13 May 2013 10:30:50 -0600
> To: alt-photo-process-list at lists.altphotolist.org
> Subject: [Alt-photo] casein and Ferrari red
> 
> 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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