Re: Polymer Plate 80% screen Weirdness

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 09:27:37 2004