U of S | Mailing List Archive | alt-photo-process-l | RE: digital negs for ziatype

RE: digital negs for ziatype

Hi Robert,

What kind of lightsource do you use? Is your working environment too

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,

-----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

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?


Rob K.