[alt-photo] Re: casein

[Paul Viapiano]

That wasn't a hamburger patty, it was a photopolymer plate...

P

On Jun 15, 2012, at 10:43 AM, Mark Nelson <ender100 at aol.com> wrote:

> My try was even worse.  
> 
> I started with 8 oz of low fat, small curd cottage cheese.  
> 
> Next I removed all the chives. 
> 
> Now I was down to 7 oz. 
> 
> I went through all the steps with ammonia and everything. 
> 
> I swear I ended up with a 4 oz hamburger patty. 
> 
> Mark Nelson
> www.PrecisionDigitalNegatives.com
> PDNPRint Forum @ Yahoo Groups
> www.MarkINelsonPhoto.com
> 
> sent from my iPhonetypeDeviceThingy
> 
> On Jun 15, 2012, at 9:26 AM, Christina Anderson <zphoto at montana.net> wrote:
> 
>> OK, let's make this clearer then because it is wrong below.
>> 
>> Cottage cheese in America is bought by weight in ounces--an 8 oz. container. Wish I could change that, but I can't :)
>> 
>> It says on the container "226g."
>> 
>> I rinsed the liquid off these curds and came up with 140g remaining curds WET.
>> 
>> In this container there is said to be 28g protein but it does not specify what kind of protein
>> 
>> I mixed 50 ml of 10% ammonia with 70 ml of plain water into this amount to come up with a very nice thickness of casein for my purposes. I first added teh 50ml of 10% ammonia and the curds immedately started to turn clear. After a very short while the entire amount was liquified (an hour or so?). I tried to print with this and it was too thick. 
>> 
>> I poured 70ml water into the container, bit by bit, to see about when it "felt" right, and settled on 70ml total water. Then some drops of thymol to preserve. I printed with this immediately.
>> 
>> In relation to your and Peter's 23% figure of dry casein from skim milk: I use 3 Tablespoons/30g of powder per cup of skim milk from dry powdered milk. I ended up with a curd the size of a large walnut that weighed 37g wet. I dried that and weighed and there is no way that it even approximated 23g dry but maybe I am reading your notes wrong. It was very close to 9g dry. I have no idea why this discrepancy but it is possible in the vinegar steps of the process that some of the casein went down the drain and that I dried the curds to a crisp or something. But wet weight of the walnut sized curd was
>> 
>> Chris
>> 
>> 
>> 
>> Christina Z. Anderson
>> christinaZanderson.com
>> 
>> On Jun 15, 2012, at 7:26 AM, Alberto Novo wrote:
>> 
>>> Chris, 
>>>> I am finding that the cottage cheese diluted 120ml to 8 oz feels almost like a 14 baume gum, and mixed equally with pot di 10% and 1/4 teaspoon dry pigment, has a nice coating feel, not too thin, not too thick and grabby.
>>> 
>>> I like these unit conversion problems!!!
>>> Why are you starting with ml and ending with oz?
>>> Let me know if I am reading correctly:
>>> You took 120 ml of cottage cheese and added ammonia up to 8 oz.
>>> 8 oz = 236 ml, so that you diluted about 1:1 your cottage cheese.
>>> Diluting 1:1 this with dichromate = 473 ml.
>>> 1/4 teaspoon = 1.23 ml, but to convert this into grams one needs the bulk density of the pigment. This may vary with the nature of the pigment
>>> I have found:
>>> lamp black 100-200 kg/m3 (0.1-0.2 kg/L, g/cc)
>>> raw Sienna 0.6 kg/L
>>> black iron oxide (Mars black) 1 kg/L
>>> burnt Umber 0.7 kg/L
>>> quinacridone red 0.39 g/cc
>>> phthalocyanine blue: 0.45-0.50 g/cc 
>>> Generally speaking, earths and oxides have a bulk density more or less twice that of organic pigments. 
>>> So, your 1.23 ml may be from 0.5 to 1.2 g depending on the pigment, and it is about 1.25 to 3%, or 0.0125 to 0.03 g/cc in the casein solution. 
>>> When I printed my caseins with red earth, I used:
>>> 0.8 g casein + 6.5 ml 15% ammonia + 3.5 ml water: this is about 8% casein w/v.
>>> Then I added 0.4 g of red earth for 1 cc of 8% casein solution, plus an equal amount of 15% am dichromate. This solution has to be prepared at the moment of use (metal oxides, as you know, react with casein).
>>> This is about ten times the concentration of natural pigment / 14 Be gum arabic I use (for earths) without flaking. 
>>> Alberto
>>> www.grupponamias.com
>>> www.alternativephotography.com/wp/photographers/rodolfo-namias-group
>>> _______________________________________________
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>> 
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