RE: what I've learned about cyanotype thru PDN

From: Eric Neilsen ^lt;[email protected]>
Date: 06/05/05-09:45:29 PM Z
Message-id: <>

Seriously. Why not use pt with NA2? Grain? I say learn to work it! :) There
will always be a place for grain in photography. Although with the digital
age upon us, I fear that those just starting out will not only wonder what
dodge and burn mean, they will also wonder what the heck film grain is : )

Humidity affects both PT and PD, but just in opposite ways. I would suspect
that it has something to do with ionization potential and that the water
inhibits the reaction by getting in the way with platinum, and helping to
facilitate it with palladium. But these are just quick ideas and should be
asked of a real chemist or at least someone with a reference to the
preferences of little electrons. Higher levels of humidity also produce more
print out, with either with FO or AFO, but at least with FO doesn't really
produce enough to alter final print quality.

Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226

> -----Original Message-----
> From: Christina Z. Anderson []
> Sent: Sunday, June 05, 2005 9:47 PM
> To:
> Subject: Re: what I've learned about cyanotype thru PDN
> Seriously??? This is so interesting. I've now added your info to my alt
> process tidbit file...
> Why does humidity affect it this way, and one metal and not the other? Is
> it what Loris says, I wonder, about the ions??? (Loris says > 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.)
> Probably another one of those things that we can surmise about til the
> cows
> come home, like crosslinked gum.
> Eric, I can make one guarantee; I will NEVER be a master pt/pd printer.
> That is 100% sure. I'll leave that to you techie types. But you're
> right:
> I only use the NA2 stuff, so only a modicum of pt in my pd mix.
> Chris
> > Chris said "So I think you may be talking about humidity being a speed
> > benefit (for sure in pt/pd, maybe in cyanotype) vs. uneven moisture,
> which
> > is not."
> > Oh master (although not of pt/pd printing), Not always. One needs to
> make
> > a
> > distinction between PT and PD when talking speed and relationship to
> > humidity. PT is slower at high humidity than at low humidity. PD is
> > slower
> > at low humidity and faster at higher humidity. Both have relatively
> flat
> > speed changes in the 50% range. This is one reason that printing PT/PD
> > printing at 50 to 60% will produce prints that don't change speed due to
> > humidity. Another aspect of PT/PD is change in color based upon RH.
> > If you make your prints with only trace amounts of PT then you may
> indeed
> > have a hard time seeing either speed or color changes due to humidity.
> Eric Neilsen Photography
Received on Sun Jun 5 21:45:48 2005

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