RE: digital negs for ziatype

[Robert Krawiec <robk64@yahoo.com>]

Hi Loris,

Thanks for the tips!

I'm in Denver, Colorado, so it's pretty dry here!

I'm using an Edwards Engineering UV exposure unit.
I'll give your tips a try and see what I get...

Thanks

Rob

--- Loris Medici <mail@loris.medici.name> wrote:

> 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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