U of S | Mailing List Archive | alt-photo-process-l | Re: finer aquatint screen revisited

Re: finer aquatint screen revisited

Hi Susan,

With good care the screens theoretically will last a long time, but they can get dings, half-moons, kinks, etc over time. Since imagesetters have become few and far between, stocking up on custom screens seems to be a good idea...or maybe Loris is interested in starting a cottage industry in Turkey, land of the cheap imagesetter output! ;-)

The purpose of my last message was to say I'm basically done looking for vendors and the requirements are less rigid than I thought, as written below. The screens I was getting from CopyGraphics were great, but there's apparently quite a bit of latitude in what one can do with a finer screen. Once I get good screens from two of the vendors I plan on buying a bunch at various sizes, then putting their contact info on this list and my procedures page.

The one param I forgot to include was the imagesetter is on the "Fine" setting (as opposed to "Coarse" or "Very Fine"). Very fine produced too much contrast.


SusanV wrote:
Hey Jon,

Thanks for the update on the screens!

One thing I didn't realize was that the screens wear out under normal
and careful use... I thought as long as they were well cared for they
would last indefinitely.  Can you elaborate on that?

I'm looking forward to trying the new screen when you get them squared
away.  Thanks for the specs, too... maybe I can find a source locally.


On 4/22/07, Jon Lybrook <jon@terabear.com> wrote:
Hi all you Poly Plate People!

Just finished evaluating some tests I did using a 2540 dpi random dot
screen make from a Scitex imagesetter.  The results are very good --
better than the 1800 dpi screen made from the Agfa Imagesetter.  There
is a washout pattern visible in the screen, probably due to exhausted
chemistry, but the good new is it doesn't seem to read in the tests.  I
think the exposure unit burns right through that stuff and so the KM73
plate, for whatever reason, doesn't see it.  End result seems to show
better tonality than 1800 dpi with no noticeable increase in degradation
of the plate.  Haven't tested exactly how many prints I can get out of
one plate yet however.  Under the 1800 dpi screen a client of mine said
he was able to get 25 before the plate started showing signs of wear,
but I don't know what his workflow is either.  There could be other
things he could do differently to increase plate longevity.

I'm going to have the vendor send me another test after the imagesetter
has gotten a PM and chemistry change to see if the pattern goes away.
I'm working on a number of leads on vendors who are willing to do this
kind of output on a regular basis for us.  Anyone interested in it could
certainly find someone with a Scitex imagesetter and get their own
screens made - Just tell them you want a positive, 80% density, 2540
dpi, random dot screen.  I'll check, but I don't think there are any
more parameters than that.

With Susan's recent success with PDN and the KM73 plates, I predict that
approach in conjunction with employing a finer random dot screen is
going to give an amazing boost to the current standard of tonal quality
and smoothness possible with this process.

Best wishes,