Re: Polymer Plate 80% screen Weirdness

Yup. It's incomplete contact with the acetate. I was exposing and getting
this problem; talked with Dan Welden about it, and lo and behold I finally
found the answer in his book on one of the pages where it talks about this
and how you have to switch to a different acetate. When I looked at my
acetate, it had a low relief pebbly textured surface on one side that was
not allowing complete contact with the surface of the solarplate. It is the
3M brand of transparency for ink jet printers from Staples.

Are you exposing the screen against the solarplate in a contact print frame
assuring tight contact? If not, it may not be the acetate's fault, but
yours.

This happened enough to me so that I thought I was brushing too hard with
the brush and doing an incomplete brushing manoeuver, causing these water
spot looking things. Then I did a drawing on one of the solarplates (no
acetate) and the problem disappeared.

Did you buy the screen or make it yourself?

I also found I had to expose the screen for 1 1/2 minutes (in a contact
print frame), to harden the base of the Solarplate well enough, before I
exposed my neg (instead of the 1 minute recommended time). This dealt with
the possibility of having the Solarplate too soft and thus possibly brushing
too hard.

Every time I do this solarplate thingy, and watch another $13 go down the
drain, it bites the big one. And believe me, Jon, I am just a novice so
take everything I say with a grain of salt. I just don't have $800 to spend
on a workshop at the moment so I am having to learn it all by trial and
error. And lots of swearing.
Chris
----- Original Message -----
From: "Jon Lybrook" <jon@terabear.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Sunday, February 15, 2004 7:05 PM
Subject: Polymer Plate 80% screen Weirdness

> Hi All,
>
> I'm starting to get set up at home to burn photopolymer plates with my
> blacklight box built from Dick Sullivan's fabulous directions in his book
> on PT/PD printing.
>
> What I'm finding is the 80% density, 300lpi screen I'm using to
> pre-expose the plate is resulting in a kind of mottling effect. Looks
> like water spots directly on the plate.
>
> Has anyone else come across this?
>
> Thanks,
> Jon
>
>
Received on Sun Feb 15 18:23:21 2004