Re: Re: Polymer Plate 80% screen Weirdness

From: Jon Lybrook ^lt;jon@terabear.com>
Date: 02/16/04-12:05:59 PM Z
Message-id: <Pine.LNX.4.44.0402161103200.26495-100000@terabear.com>

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 like‚€”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 area‚€”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? 
> > > > 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 12:06:18 2004

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