RE: digital negs for ziatype
Hi Robert, What kind of lightsource do you use? Is your working environment too dry? IME, 15 minutes exposure is quite long for Ziatypes w/ digital negatives. My standard printing time (for max. black) w/ a bank of BL fluorescent tubes is around 6 - 8 minutes (I get around 27 - 28 steps w/ the 31 step tablet = log 2.8 DR). Using a more contrasty mix will help in getting paper white (try adding 1 drop of 1.25% Ammonium Dichromate per 10 drops of coating solution = this should give you a DR around log 1.7 - 1.8 = 17 - 18 steps w/ the 31 step tablet), but you should note that 2200 OEM inks have plenty density (you can try to increase ink amnt. in the printer driver, + %5, %10, %15)... BTW, Ziatype is faster and gives better Dmax in high humidity (>= 70%), try to print as soon as the paper is surface dry. (= Wait not more than 5 - 10 minutes after coating + do not use a hot air stream to dry the paper!) You may try to put a piece of impermeable substrate (such as Mylar or Yupo...) under the paper to minimize humidity loss during the long exposure. Hope this helps, Loris. -----Original Message----- From: Robert Krawiec [mailto:robk64@yahoo.com] Sent: Tuesday, March 27, 2007 7:40 AM To: alt-photo-process-l@usask.ca Subject: digital negs for ziatype Hi All, I've been trying to create digital negatives for ziatype on a 2200 with not much success and I was wondering if anyone out there with expertise could comment... I'm using no contrast adjustment in my mixture, just FAO and #3 solution, on arches platine paper. I'm using black & coloured inks (i.e. not tried PDN system yet) on pictorico OHP. My problem is that I'm exposing for 15 mins with my UV lights and still not seeing dmax (close though). My step table though is not showing paper-white. The last few steps are showing clear tones of grey. My guess is that I need to mix a more contrasty mix... Any other ideas or suggestions? Thanks Rob K.
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