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

Re: pyro and cyano


I have wondered whether hydrogen peroxide was good for the print as well and have not heard any definitive answer. I only use it when I need to see how dark the lower values would get - it hardly affects the lighter areas. With diluted cyanotype emulsion the effect is minimal as well.

The only reason you thought I tamed the process was because I hid my huge trash can full of reject prints! I've always agreed with what you said, that cyanotype may seem easy but it's the hardest to pin down.


On Apr 10, 2009, at 11:45 AM, Christina Z. Anderson wrote:

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.

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.

And who the hell cares about the archivalness of my prints--like I'm going to be famous one day????

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.

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.

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.

Christina Z. Anderson
----- Original Message ----- From: "BOB KISS" <bobkiss@caribsurf.com>
To: <alt-photo-process-l@usask.ca>
Sent: Friday, April 10, 2009 8:06 AM
Subject: RE: pyro and cyano

Does using the hydrogen peroxide cause any problems during
processing or after? I use it because it gives me the final depth of blue
quickly so that I can judge if I have the correct exposure.

-----Original Message-----
From: Christina Z. Anderson [mailto:zphoto@montana.net]
Sent: Thursday, April 09, 2009 11:22 PM
To: alt-photo-process-l@usask.ca
Subject: Re: pyro and cyano

Chris, when you say "six stops"
--- how many steps on the 21-step is that ?

Hi Judy,
6 stops is 12 steps on a 21 step tablet (1 step=1/2 stop) or 18 steps on a
31 step tablet (3 steps= 1 stop). This is why I don't talk steps because it

is confusing with whether one is using a 21 or a 31 or a 44, but a stop is a

stop is a stop.

Yes, cyano gets darker as it oxidizes. I never use, and never recommend,
hydrogen peroxide because eventually the print will turn that nice darker
blue anyway.

(If I display ignorance,
please excuse.... But I live in a 21-step dimension, not a "stop"
dimension. In fact when I strayed into the wet darkroom last month on a
different mission, I couldn't even make the safelight go on !)

In any event, my rule of thumb for an average neg in simple cyano was 8 or

9 steps, tho I found many ways to modify that. For instance, pages 34
thru 37 of Post-Factory #5 ("Managing the Blues") show differences from
light source (sun vs. UV bulbs), paper (Strathmore Artists v. Whatman Fine

Print, among others) proportions of parts A & B (as discussed on this list

by... Sandy?, Bob Shramm?, others ?) a while back; time on the paper
before exposure, delayed development, double coating (according to paper),

acid "prebath" ("tends to extend and deepen range very dramatically"),
etc. etc. etc.

That issue is dated "August 2000", so (BELIEVE ME !!!) I've forgotten the
details (the above is from a quick skim... but I'm not printing cyanotype
these days, and need that disk space ...ie, what's left in the brain ...
for current endeavors, so am TRYING to stay away from this topic... Tho,
since you insist.... my eye lights on mention that, to my surprise, I
discovered that "dry down" in cyano, goes on, not just for one day, but
several ... But you knew that ?

There are also 21-steps A through D2 of various ranges & why (p. 37). But
as in "devil get thee behind me," I change the subject: Another P- F (from
around then) shows a "Cyanodyke" -- what the photographer called her
vandyke brown prints over cyanotype. The print was very pretty, with nice
combined tones (tho in repro b&w only). As I recall, she didn't mention
bleaching, tho of course in the other way around -- cyano over vandyke
brown -- the silver gets bleached by the potassium ferricyanide in the
cyanotype. A short item, but if I locate it, I'll cite.


not suitable for cyanotype as it is for other processes that have longer
tonal ranges, unless one were to contract the tonal range of the pyro neg

to match cyano--or have subject matter that is tonally contracted anyway.

BUT, and this is my question: does anyone know the maximum DR possible
in a pyro neg? I do not have a UV densitometer. And, from memory (which

obviously doesn't serve me too well so please answer this, too) a film
negative can actually record up to 13 stops of info, pt/pd about 10, BW
paper about 7, and cyano about 6...you get my point perhaps.



OHHH man do I need to get back to work, this is too fun posting all these

silly visuals, and hopefully someone will benefit except me :)

Christina Z. Anderson

__________ Information from ESET NOD32 Antivirus, version of virus signature
database 3999 (20090410) __________

The message was checked by ESET NOD32 Antivirus.