Re: Cyanotype woes
Keith, Don't panic...help is on the way... It should be 20g of FAC which is 10 tsp per 100ml of water or 17 tablespoons (about) for 500ml IF you are using the green powdery FAC that weighs half as much as the brown scales. So plop more FAC in there. With the revised edition of my Alt manual I had to correct that because the FACS weigh so different. However, I have tried all kinds of formulae of cyanotype ratios, according to Mike Ware's book, and they don't look much different except in speed as far as blue is concerned. In fact, I have Sam Wang's chart that maps out the different formulae that people use for cyanotype and I finally had to ask Mike offlist is this possible that cyanotype could be so uncritical as far as dilution/ratio goes. He addresses it in his cyano book. And I have not yet had any bleaching of the layer with gum--in fact, the layer of cyano, due to the acidity of gum, gets deeper when the next layer goes on. I only use a 15% dichromate and a 1 + 2 gum so maybe your am di is stronger, your gum is weaker, or whatnot. I think Don Bryant has also said he experiences bleaching of the layer, though. I might address the alkalinity of your water, because I know for one thing that Fabriano Artistico is a very alkaline paper and I get lots of namby pamby cyanotype on that paper and had to, in fact, increase my exposure and do a different curve for that particular paper. I HOPE the paper you have is the same batch of Masa so the paper did not change in manufacture like Platine did. Chris ----- Original Message ----- From: "Keith Gerling" <keith.gerling@gmail.com> To: <alt-photo-process-l@usask.ca> Sent: Wednesday, February 27, 2008 8:37 AM Subject: Cyanotype woes I'm at the end of a month-long project printing gum over cyanotype and I seem to have run into a problem. I'm not at all experienced in cyano, but for weeks now I've been getting perfectly scrumptious prints on Masa using three different batches that I've found laying around that vary from 6 to 8 years in age. One of these batches I mixed up myself, one was from a friend, and one is in Bostick and Sullivan bottles and all of them perform identically. Running low, I mixed up a fresh batch last week with fresh chemicals and distilled water. Totally different results. The old batches gave me deep Prussian blues almost immediately. The new stuff produces weaker looking prints that are much more cyan (greener). But the biggest issue is that the prints bleach out in the gum development stage of the process. Granted, my well water might be alkaline, and the older prints did bleach out a tad, but I with red and yellow gum layers I was getting some of the deepest blacks I've ever seen in any process. With the new batch everything looks very anemic. I'm using equal parts A to B (as before, although I've tried 2 A to 1 B with even worse results). Having no scale, I used the measuring spoon method Chris provides in her book. Assuming that the math is correct (I used 8 tablespoons + 1 tsp FAC for 500ml) what can explain this difference between old and new chemistry? I'm running out of time, as I have to show this work in two weeks. Any ideas? I'm thinking that I have three options" 1) use a more concentrated solution of FAC, 2) dump vinegar in the gum development water, 3) finish the project in 6 years when the Cyanotype solutions have properly aged. Thanks! Keith
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