[rollei_list] Re: Rodinal, TMax, scanning

Bob, you were probably wet-mounting the negatives on the drums --
the wetting agent eliminates any rings.  The problem only surfaces
(pardon the pun) when you are putting negatives directly on the
flatbed scanner glass, without any mounting fluid.  Then you have
substrate (in the shadows) touching the glass, and Newton Rings
are everywhere.  I found this to be an especial problem with thin
emulsions like Tech Pan, but Tri-X almost never causes problems
like this, at least when scanning it emulsion-side down.  (With a
flip in PS to reorient the image.)
 
-------- Original Message --------

Date: Sun, 16 Oct 2011 16:04:30 -0500
From: Don Williams <dwilli10@xxxxxxx>
Subject: [rollei_list] Re: Rodinal, TMax, scanning

At 08:11 AM 3/21/2011, Bob Smith:
>I read this from Sanders this morning and I wanted a little
>clarification - I could be misinterpreting the thought. I've never
>heard of underexposed negs causing Newton Rings. Am I understanding
>this correctly? I spent many years selling both high-end drum
>scanners (Hell Graphics / Linotype / Scitex - along with flatbed
>scanners from Iris / AGFA, etc) - and I never recall hearing Newton
>rings can be caused by underexposed negatives. Now I'm curious and
>just looking for some clarification.
>
>Thanks.
>
>Bob Smith
This is a response to a fairly old post but I can say that as far as
slides are concerned, at least for some types, if they are
under-exposed there are less "bumps" on the emulsion side and that
does make an environment for Newtons rings.

DAW

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