[Alt-photo] suggestions about cyanotype curve

Bob Cornelis bob at colorfolio.com
Wed May 24 00:47:14 UTC 2017


I can't tell you how much better I feel after reading your response - to
hear that I am not alone in finding the cyanotype process challenging is
reassuring. You always hear how "easy" it is! I think it is very easy to
make a reasonable cyanotype print but hard to make a consistently great

I am going to post my target and curve pixs on the FB group now that I no
that no attachments are allowed on the forum.

I've been monitoring the humidity in my studio - I'm in the SF Bay Area in
CA so the humidity levels are pretty good and consistent. I'v been running
about 60% lately. But have been looking at humidifiers.

I have use vinegar in the past, contains acetic acid. I thought it would
behave as citric acid does but I'll look into that idea.

I am going to play with ink density, everyone seems to be pointing me in
that direction. I have taken to printing a real image with the target and,
to be honest, my current curve is generally giving me pretty good prints. I
am interested in taming the highlights, though, and this is proving a good
exercise to learn a lot more about the concepts and inner mechanics of neg
making. I own PDN but have not used it yet - my reading of the PDN ebook
seems like it is a more complex and sophisticated version of Mrhar's
method, though conceptually they seem pretty similar with regard to the
steps taken. Thought I'd start with Mrhar and migrate to PDN as an
evolutionary step. I could be reading the relationship of the two
incorrectly, however.

Thanks again for the response!

On Tue, May 23, 2017 at 1:31 PM, Christina Z. Anderson via
Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org>

> 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
> _______________________________________________
> Alt-photo-process-list | altphotolist.org


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