[filmscanners] Re: Avoiding Newton rings

["Arthur Entlich" <artistic-1@shaw.ca>]

Anthony Atkielski wrote:

> 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.
>
>


If you are still getting Newton rings with the anti-newton glass, (or if
only one side is anti Newton, then from the regular glass side), you may
want to try the Mylar on the one side which is contacting the regular 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.
>


The term "pepper grain" isn't about film grain, but I believe it more
refers to grains of pepper(corn) (the spice) than to film grain.  Since
I didn't coin the phrase, I can't say what the originator had in mind,
but the result of these bubbles being visible in the scan are small soft
focus blackish dots, like that of finely ground peppercorns.  As I
understand it, dICE eliminates these due to it being an irregularity in
the emulsion which is picked up by the IR scan, and therefore removed.

This artifact is not picked up by all scanners, BTW.  It is mainly a
problem with the Minoltas and likely the Nikons when dICE either is not
used or is unavailable as an option.  I never have seen it on the
Polaroid SS4000+, for instance.

Art




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