what I've learned about cyanotype thru PDN

Well, I've spent the last several days developing my own curves for
cyanotype, and then gum will be next, using Mark Nelson's PDN system. The
side benefit of doing this is finding out all the other stuff about a
process that you didn't think to know. Not that any of this is new to you
longtime cyano printers, but there may be newbies out there who might
benefit from my findings: And not that my findings are gospel, as I know
there will be someone who will find this not true. Hey, postmodernism...no
absolutes, right?

For one, I started on sized Fab Traditional White cold press, and then
switched to Arches Platine, preferring a smoother paper for the curve
process. Platine was a stop faster than other papers I tried (whether sized
or not). And has smoother tonality. If I were to do straight cyanotype (no
gum on top) this would be my paper of choice.

I learned how the color of cyanotype changes from one paper to another, and
in 24 hours on a paper. It is a beautiful pale thalo blue on Platine, a
more navy blue on Fab and BFK. The following day it is a deep thalo on
Platine and a deeper navy on Fab. (Traditional cyano, 2A:1B) Thus it is
important to wait 24 hr before developing your curve.

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.

I learned that using hydrogen peroxide doesn't do much of anything except
show you the deepened blue color the paper will become in 24 hr. on its own,
anyway.

I learned that both tween and longer drying time make for a duller print
(sometimes a good thing on contrasty paper I would suppose) and to be
consistent in developing your own curve you need to be consistent with your
drying time.

My guess is that each paper will not only require a different exposure time
but its own tweaked curve AND its own specific color neg, too.

My goal is to get the perfectly tonal cyanotype and then see how that
affects the tricolor gum process. It may be that each gum color requires a
different curve, too, being that the pigment may act as a filter to light in
the same way that a filter on front of a camera changes the tonalities in a
BW neg. Or it may be that gum is such a flexible process that curves aren't
important. Or somewhere inbetween, but I won't know the answer to this
question until I print my old way side by side with the PDN negs. I do know
that the cyanotype curve works beautifully and is a great improvement over
my old way.

I'm tellin' ya, it is worth it to learn how to make your own curves, because
you don't have to wait for someone to come up with one that may (or may not)
fit your own computer/printer/scanner/paper/process combination. It's sorta
like paying your dues, once you've learned the process it makes infinite
sense to put in the time and be confident that your print will be the best
it can be. As Judy says, one little step wedge (tablet/strip/test) speaks
volumes.

My 20 cents for the week--back to work (I just have to share this with
SOMEONE because when I show my husband my tonal palettes he just yawns. And
Sam left for China!!)
Chris
Received on Sat Jun 4 18:35:13 2005