RE: pyro and cyano
DEAR CHRISTINA ET AL., 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. CHEERS! BOB -----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. Chris (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/ >> __________________ >> > __________ Information from ESET NOD32 Antivirus, version of virus signature database 3999 (20090410) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com
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