From: DigitalBlackandWhiteThePrint@yahoogroups.com
[mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Ernst
Dinkla
Sent: Friday, March 23, 2012 9:31 AM
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Subject: Re: [Digital BW] Re: Epson 4990 Scanner Question
On 03/23/2012 03:10 PM, faeofavalon wrote:
> Ernst,
> I will try what you said about masking it first. I neglected to mention
> the most important thing - the negatives are overexposed (simply because
> my Holga was set to "Bulb" without my knowledge!) so they are dense.
> HOWEVER, I can see through them when held up to light so the information
> is there.
>
> On another subject, yes I do scan directly onto the glass but I never
> seemed to have a focus problem. Is using the mediocre film holders that
> Epson gives me, advantageous to focus?
>
> AnnMarie
Depends, the Epson Perfection scanner models have no active focusing in
the scanner, it is a fixed focus design and not perfect. One 4990 may
have the focus on the glass bed, the other one 3 mm above the bed. In
theory the best focus should be halfway the height between the film
plane in the holders and the glass bed but the deviations are way beyond
that. Much is compensated by the wide DOF of the lens system but there
is something to gain there by adjusting the film holders. See this
article written 8 years ago on the 2450 model:
http://www.normankoren.com/Tutorials/Epson_flatbeds.html
If you want to include the frame edges there is the problem that little
film surface is left for keeping the film flat in any holder. If you
also want to reduce Newton rings etc that would occur in using glass in
contact with the film then there is only one solution that really keeps
the film plane and avoids Newton rings without loss of detail etc: wet
mounting. Doug Fisher makes custom wet mount holders and has some docs
on how to use them, There must be something I wrote among them. Doug's
holder has also adjustable nylon screws to get best focus. He has more
holder types too including anti-newton glass inserts.
http://www.betterscanning.com/
--
Met vriendelijke groeten, Ernst
Shareware now:
Dinkla Gallery Canvas Wrap Actions for Photoshop
http://www.pigment-print.com/dinklacanvaswraps/index.htm
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