[filmscanners] Re: Avoiding Newton rings

["Anthony Atkielski" <anthony@atkielski.com>]

Arthur writes:

> If the texture is visible in scans, it would
> show up on either side, unless the depth of focus/field
> had a very fast drop off to limit the ability
> to have the texture in focus.

Or you can simply make the texture of the anti-newton glass finer than the
resolving power of the scanner, in which case it becomes invisible.  I think
that is what Nikon does, as I've never seen any trace of artifact from the
anti-newton glass.  It's hard to recognize it as anti-newton glass,
anyway--it's not like it is thickly frosted or anything, only slightly matte
in appearance compared to the normal glass.

> As you may recall, Roger Smith found that the
> most surface transparent layer on the emulsion
> side seems to be the one containing the "bubbles"
> which were being recorded by some scanners are
> "pepper grain".

When I examine emulsions under a microscope, the bubbles are easy to see.  I
can't tell if they influence grain or not in scans, though.



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