Re: Arches Aquarelle and Gum - cyanotype recipe
Loris, Here, belatedly is the cyanotype recipe that I use - one which I think is very good indeed. stock A Ferric Amonium Citrate (green scales) - 68 grams Oxalic acid - 1.3 grams Water (distilled) to make 250mls stock B Potassium ferricyanide - 23 grams Oxalic acid - 1.3 grams Ammonium Dichromate - 0.5 grams Water (distilled) to make 250mls I have only ever used a half and half mix, and never tried 2xA and 1xB whcih I understand is the preference of some - with the old classic formula in particluar. I'd be interested to know if you try this recipe - and if you know the humidity of where you are working there in Turkey - just to see what results you get. I'm thinking that humidity is important with cyanotype - although probably not as much as I now well understand it is with Pl and Pd (thanks Mark!) FWIW (and it may make no difference at all) I don't simply add 250mls of water but start with 200mls and then add enough water so that the solution is 250mls. I suspect it makes no difference at all since there are so many different recipes out there and goodness know how someone (which, in this particular case, may well have been Arnold Gassan since I have this from Carson Graves who was a collaborator with Gassan in his researches and book) came up with the rather precise measurements. I wonder if 68 g or 70g is really an issue. I'm sure someone will correct me, in fact it would be nice to know. I think Gassan also gives a recipe for teaspoon measurements. cheers Catherine ----- Original Message ----- From: "Loris Medici" <mail@loris.medici.name> To: <alt-photo-process-l@usask.ca> Sent: Tuesday, February 20, 2007 6:25 PM Subject: RE: Arches Aquarelle and Gum > Thanks Catherine. Adding oxalic acid to the sensitizer may help in > printing on buffered papers, but with the added expense of making the > surface gritty and causing abrasion due to formation of calcium oxalate > (kidney stone) cystrals on surface - you practically rub the sharp > crystals over the paper white sensitizing and scratch it... Also, tonal > gradations suffer due to relatively grainy results. Probably the paper > you're using is unbuffered -> since you are happy with the results. > > BTW, (this is especially for Anne) I tried Weston paper samples (given > to me by Sam - thanks again!) with classic cyanotype and it works like a > charm. Anne, forget about Masa paper -> buy Weston paper! > > A warning: since the paper base is quite warm, the result is a more > greenish blue... > > Regards, > Loris. >
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