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

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.
> Judy
>> 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.
> [CUT.....]
>> http://christinaanderson.visualserver.com/Text_page.cfm?pID=2448
>> 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 :)
>> Chris
>> __________________
>> Christina Z. Anderson
>> http://christinaZanderson.com/
>> __________________

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