RE: what I've learned about cyanotype thru PDN

While we're on the subject of cyanotypes and our own curves, all the lit i've read on the subject implies that the paper can be exposed about an hour after coating (or, enough time to dry). I've found that produces washed out images after the bath. But if I let the paper dry overnight, i get a really strong prussian blue color...i even found an old coated and unexposed piece of paper, i may have overexposed it...i lost a lot of detail but it produced a stunningly brilliant blue.
 
cheers...trevor

Loris Medici <loris_medici@mynet.com> wrote:
Hi Christina, thanks for sharing your experience.

I always thought that the lavender color is connected to the alkalinity of
the paper. The more alkaline the paper, the more lavender color you get. I
say this accoding to my experience with ammonia bleach - tannic acid toning.
When you place the cyanotype in ammonia solution the color turns to lavender
first and then the alkaline solution bleach the print starting from the
highlights.

In my understanding the speed should be faster when the "paper" is more
moistened - because more iron(III) ions are free to act as a sensitizer. The
constast also should be lower - because the emulsion is more sensitive to
light. And if the paper is more dry then there would be less free iron(III)
ions, therefore less speed and more contrast.

I'm not saying that what I say is concrete and exactly true. This is just
what I concluded according my observations. If I'm saying something wrong
correct me please.

Regards,
Loris.

-----Original Message-----
From: Christina Z. Anderson [mailto:zphoto@bellsouth.net]
Sent: 04 Haziran 2005 Cumartesi 20:36
To: Alt list
Subject: what I've learned about cyanotype thru PDN

...

I learned when printing out my tonal palettes of 101 steps that any bit of
moisture left in the solution produces a lovely lavender, but it screws up
the density readings because it is lighter--meaning moisture will produce
less exposure. This doesn't change the next day.

...

"The optimist believes this is the best of all possible worlds.
 The pessimist fears it's true" - J Robert Oppenheimer
 
http://www.geocities.com/tr_cunningham

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Received on Sun Jun 5 03:26:30 2005