[alt-photo] Re: casein

[Mark Nelson]

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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