RE: Glycerol as humectant for POP Pd prints at low RH
Thanks Sandy, But we have to clear the longevity issue -> will this practice affect the longevity of the print considerably? Regards, Loris. -----Original Message----- From: Sandy King [mailto:sanking@clemson.edu] Sent: Sunday, February 25, 2007 11:41 PM To: alt-photo-process-l@usask.ca Subject: Re: Glycerol as humectant for POP Pd prints at low RH Loris, Congratulations on taking the time to test that premise. It is potentially a very useful piece of information. Now, if more pt/pd printers would take the time to learn carbon as you have no telling what kind of innovations we might see!! Sandy King At 11:18 PM +0200 2/25/07, Loris Medici wrote: >Hi all, > >Probably I'm not the only smart person to tried this before but >since I haven't found a reference in the list archives, I decided to >share: > >I was having hard time making cold/neutral toned POP Pd prints >lately; the RH of my darkroom changes around 25-30% and printing w/o >drying thoroughly (in other words: with almost wet paper) isn't a >good choice since I'm using a relatively weak digital negative >substrate and printing on almost-wet paper = ruining the negative >due excess humidity. (The negative substrate I use is Ultrafine >Crystal Clear.) I also don't prefer to use a thin (1-3 mils) >polyester sheet between the negative and the paper because sharpness >will suffer... (I'm printing using a 11x14" contact printing frame >and a bank of BL tubes.) > >Anyway, given the above criteria, I decided to put glycerol >(glycerine) into my coating solution. Since this compound is used as >a humectant in both carbon printing (tissue will retain humidity >when some glycerol is present and won't brittle) and silver-gelatine >emulsion making, I thought it may help me in retain humidity in the >paper -> letting me get cold/neutral tones. > >It works! I added a drop of glycerol per 10 drops of coating >solution, dried the paper for 10 minutes and got a neutral print. >Without the glycerol - keeping all other parameters constant - I >would get a warm (brown) print. > >Do you think adding glycerol will affect longevity? I'm using very >little... (0.1ml per 1ml coating solution) > >Regards, >Loris.
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