U of S | Mailing List Archive | alt-photo-process-l | Re: pyro and cyano

Re: pyro and cyano

Hi Christina,

10 Nisan 2009, Cuma, 6:45 pm tarihinde, Christina Z. Anderson yazmış:
> Bob,
> I quit using the hydrogen peroxide because it was questioned to perhaps
> compromise the archivalness of the paper and it was unnecessary because
> the
> print would eventually get to that dark blue anyway, PLUS it seemed to
> bleach the print a bit, though this latter is only subjective to me and
> another person or so.

I don't think it will hurt the archival qualities of the paper if you use
very little like a cap (5-10ml) into 1000-2000ml water, keep the bath sort
(30-60 seconds is more than enough) and rinse well afterwards. That's what
I do; I experience no bleaching at that concentration and timing...

> BUT this is my question--does the hydrogen peroxided print actually get
> darker blue than one that oxidizes over several days?  So if it gets
> darker,
> there would be a benefit to it.  I have not tested this.

No it doesn't get darker. You just get the final result (w/o waiting a
couple of days) as soon as the print is completely dry.

> ...
> Let me tell you, people complain about gum being fickle, I find personally
> in my practice cyanotype the most fickle process of all.  I can only chalk
> it up to the fact that humidity and coating plays a way greater part in
> that
> process than people imagine.  I know Sam Wang tames it beautifully.

Just because of this, I think it's a wonderful process to enter the
alt-process world. Everything else (well, most...) looks like piece of
cake after being able to achieve consistent success with cyanotype. I was
shocked to find out how pt/pd is so much easier compared to cyanotype, for

Maybe it's the other way; cyanotype tames the printer ;)

> I also find that it is very unpredictable with my students in literally
> every class I have taught on alt.  Yesterday, one student used the same
> neg
> and curve and the print was completely overexposed and unusable.  And I
> know
> he is not a student that would leave the lightbox on and go out for a cup
> of
> coffee.

It was that way to me (unpredictable) until I finally realized that it was
due extremely high sensitivity of the process to the ambient/paper
humidity levels. Predictability/consistency came right after I decided to
force dry (bone dry) the paper after letting it soak the sensitizer for
about 10 minutes using a hairdryer at hottest setting and sealing the back
of the paper using a mylar sheet while exposing it. Ta da! That was the
trick for me. I haven't got even a single non-usable print after that.

BTW, try to bleach the unusably dark prints in 20% oxalic acid (following
a thorough water rinse) to salvage them... (This was mentioned somewhere
in Mike Ware's book IIRC.)

> But I am always combining cyanotype with another process, either gum or
> palladium, the latter which I just love so I actually use it frequently. I
> think I just need to really delve into Mike Ware's book.

Yeps, so much useful info. I learn more every time I get it into my hands!