[alt-photo] Re: casein cont...
zphoto at montana.net
Mon Oct 24 18:57:30 GMT 2011
Matti, having pure dark and pure white sounds like a curve issue, not an exposure issue. I make a very dark and dull negative, one that is even duller than gum. For instance, if I have a gum curve utilizing about 70% on a 100% scale, casein is only at 40-50%. Hard to explain but very flattened curve. So it may be your negs are too contrasty and your exposure too long. BUT I am not using Blacklow's formula.
I found that am di was overkill but I didn't find that it didn't work.
Christina Z. Anderson
On Oct 24, 2011, at 12:45 PM, Matti Koskinen wrote:
> On 24.10.2011 19:05, Christina Anderson wrote:
>> one other thing matti i am using only a 10% potassium dichromate, even less therefore than my usual 15% ammonium dichromate for a 6 minute exposure with gum.
>> do you mean "no detail" meaning that the highlights lose detail when you brush? or the print in general is low contrast?
>> Christina Z. Anderson
>> On Oct 24, 2011, at 9:04 AM, Matti Koskinen wrote:
> the print shows only very dark or pure white parts. I just mixed curd+1% ammonia, and in unblinkingeye-site recipe it'll take 24 hours to all the curd to dissolve. Laura says she mixes the curd and ammonia with an electric blender and uses the stuff immediately. I tried with Sienna colour a print and even one hour exposure revealed only slight image. Looks like the casein goes bad the older it is, as yesterday the exposure times were shorter. The Sienna print was coated only by brushing and it didn't show the white lines as using black colour. Also Laura uses ammonium dichromate and I potassium. Could there be a reaction different than mixing amm di with casein, which contains ammonia as pot di with ammonia?
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