[Alt-photo] suggestions about cyanotype curve

Christina Z. Anderson christinazanderson at gmail.com
Tue May 23 20:31:36 UTC 2017


Dear Bob,

I feel your pain. I felt it a lot this semester.

First, very unfortunately, the list doesn’t allow attachments so you have to post them somewhere online. I think this is why a lot of alt stuff has gone on FB now. Can you post it on FB to the alternative photography FB page?

Two, what about humidity? Cyanotype is very very responsive to humidity. Humidify your darkroom greatly and you’ll notice the highlights printing better for you. I had a bitch of a time with the students this year mid winter in the school lab. We actually had to presoak the paper and then dry it mostly before coating! So there was a modicum of humidity in the paper; it was cool to the touch and slightly limp. The alt lab is too big to suitably humidify it unless we get an industrial humidifier or build a humidity chamber which hasn’t happened yet.

Three, an old trick is to put vinegar in your water wash. Don’t know whether vinegar and citric perform the same function. But all these changes you make have to happen at the calibration level, too.

Four, if you are using black ink in the mix, which is very contrasty for cyanotype, people have suggested lowering the ink density and this is good only if you have made sure, as Keith said, to make your maximum black at the 100 step mark. In other words, exposure takes care of the shadows, the negative takes care of the highlights. If, on a step wedge, you have two steps of blocked up black (blue) and know for a fact an accurate step wedge calibration time to only have the one step black, it’s the negative’s problem-too dense, too contrasty….mostly.

Five, a cyanotype curve is fairly drastic once created, with a steep rise at both ends of the curve and in the middle a flatter line. It is probably the most contrast-reducing curve I make, next to casein. Believe it or not, gum is more contrasty, though I usually do double duty with the same curve for both when printing gum over cyanotype.

Six, if there is any process that gives me fits, it is cyanotype. You can do a perfect calibration but with humidity, coating mix, FAC brand, coating amount, you have to be rigorously accurate with every step to properly calibrate. But surprisingly enough a good print can be made without a perfect step wedge because it looks better with drama in the darks. I might suggest that every time you print that Mrhar step wedge you do a print of an image alongside it and see how it looks in image form and not just step wedge form. Oh, I think you’re using Ware’s, though, which is a one-solution, easier to control that way.

I don’t know Mrhar’s system, but it sounds to me like you may have chosen a too dense color. 

Everything I know comes from 13 years of working, and now teaching, PDN, so my information applies to that and not, say, QTR where I think the driver gets told how much or how little ink and what color to lay down hither and thither (?).

OK, I think that about sums it up. Can you tell I have been making lists lately? And doing inventory :(

Chris


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