Re: Re: Polymer Plate 80% screen Weirdness

Here in primitive little New Zealand we use a piece of plate glass and the
sun......talcum still recommended tho...Kate
----- Original Message -----
From: "Jon Lybrook" <jon@terabear.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Tuesday, February 17, 2004 7:05 AM
Subject: Re: Re: Polymer Plate 80% screen Weirdness

> Thanks Jan.
>
> I just called and got a price quote of $219 for a new rubber blanket. I
> could be well on my way to a frame vacuum that is not 40 years old for
> that much! Something tells me I'm going to try the talc route...
>
> Jon
>
>
> On Mon, 16 Feb 2004 jpptprnt@verizon.net wrote:
>
> > Jon
> > Shake on a little bit all over, then tap the side of the plate (holding
it
> > vertacly) and knock most of it off. Brush the remaining baby
powder/Talc off
> > with a clean soft brush (hake works well). It will look like nothing is
on the
> > plate but it is. It does not take much.
> >
> > hope this helps
> > Jan Pietrzak
> >
> > > From: Jon Lybrook <jon@terabear.com>
> > > Date: 2004/02/16 Mon PM 05:09:09 GMT
> > > To: alt-photo-process-l@sask.usask.ca
> > > Subject: Re: Polymer Plate 80% screen Weirdness
> > >
> > > I think this is kind of what I'm seeing, only there are dozens of
them,
> > > and very small, about the diameter of a pin head and larger. I'm
getting
> > > a fair amount of pressure, but maybe the pad needs to be replaced.
> > >
> > > Don't I need pure talc, or will perfumed baby powder be okay? I'm a
> > > little concerned about what affect fragrance and other additives might
> > > have on the plate and/or film.... Hell, I'm a little concerned what
> > > affect talc will have inside my frame vacuum!
> > >
> > > Jon
> > >
> > > On Mon, 16 Feb 2004 Ender100@aol.com wrote:
> > >
> > > > I'm not sure what it looks likeâ?"dusting talc reminds me of the
problem
> > with
> > > > scanning negatives where talc or mounting fluid is used to avoid
Newton's
> > > > rings. Here is a website showing the effect:
> > > > http://physics.ucsd.edu/was-sdphul/labs/demos/optics/NEWTRNGS.html
> > > >
> > > > It does indeed look very much like a mark made by a water
drop....this is
> > > > probably the culprit.
> > > >
> > > > The Newton's Rings effect would also be exacerbated by uneven
pressure on
> > the
> > > > negative/plate contact areaâ?"which could be due to eneven pressure
of the
> > > > vacuum table membrane beneath the two.
> > > >
> > > > So, get out your old can of baby powder....
> > > >
> > > > Hope this helps.
> > > >
> > > > Mark Nelson
> > > >
> > > >
> > > > In a message dated 2/16/04 1:59:42 AM, jon@terabear.com writes:
> > > >
> > > >
> > > > > Thanks for your input Mark. Not sure how the pebbling up against
the
> > back
> > > > > of the plate would do anything to affect the film on top, but who
> > knows?Â
> > > > > I'm wondering if the pebbling on the frame vacuum hasn't somehow
> > affected
> > > > > the screen in areas where the two came in direct contact with one
> > another.
> > > > >
> > > > > I've read on Strange Ross' site he uses a dusting of talc on the
plate
> > to
> > > > > remove air bubbles. I may try that and/or call Peter at Alpha
Graphics
> > > > > and see what he thinks. I will let the list know how it goes.
> > > > >
> > > > > Thanks!
> > > > > Jon
> > > > >
> > > >
> > > >
> > >
> > >
> >
>
>
>
Received on Mon Feb 16 13:47:07 2004