Re: Flatbed scanners (Re: Film Scanner Questions)

----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Monday, December 19, 2005 3:22 PM
Subject: Flatbed scanners (Re: Film Scanner Questions)

> Anyone interested in scanning LF films/plates on flatbed
> scanners, a
> paper published in vol 68, issue 5 (most recent issue) of
> Journal of
> the Society of Photographic Science and Technology of
> Japan is of
> great interest. Nakatsuchi et al. used MTF test target and
> tested 4
> flatbed scanners (2 Epsons, 2 Canons). They were
> interested in
> selecting a scanner to archive historical silver gelatin
> plates.
>
> One thing they found is that, the actual resolution of
> Epson GT-X700
> and Canoscan 99x0F (where x is 0 or 5) are only half the
> value
> actually set when scanning. That is, if you se the
> resolution to be
> 4800dpi, you'll get 2400dpi worth of information, but if
> you set the
> scanner to 2400dpi, then you'll only get 1200dpi worth of
> information. This is a waste of 4x storage space for the
> same
> information. On the other hand, they found that Epson
> ES-10000G gave
> actual resolution very close to the nominal scanning
> resolution. ES-10000G is also the only model with focus
> adjusting
> mechanism among the scanners mentioned here.
>
> From all these info, it is pretty essential to select a
> good scanner
> with double the resolution you need, and always scan at
> least double
> the resolution you need, and use a decent image
> manipulating software
> to downsample the image, rather than letting the scanner
> or scanner
> driver do this work. (However, this is pretty consistent
> with what
> most people found by experience... nothing new here,
> except that
> Nakatsuchi et al. did the right thing to obtain firm
> evidence.)
>
> They decided to go with ES-10000G and they also determined
> the best
> part of the scanning area in terms of resolution, made a
> plate holder,
> and came up with a good focusing strategy.
>
> They also say that none of the flatbeds is suitable for
> MF/35mm films.
>
   Is this paper available in English?

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com