Re: Polymer Plate 80% screen Weirdness

Thanks Christina,

I'm using a screen made at Alpha Graphics and am using Pictorico OHP
transparencies. I am using a frame vacuum. If I watch the exposure of
the screen, I do see some bips (my own term) in the surface of the film
from the pressure, but it's otherwise smooth. I don't know what could be
causing the little indentations. The screen also comes off the frame
vacuum perfectly smooth too (no kinks or bips -- they only exist during
the exposure).

Jon

On Sun, 15 Feb 2004, Christina Z. Anderson wrote:

> 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 18:48:00 2004