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Re: Digital Scanners



Hello

We purchased a PS7000 to sustain a digitisation project over a large
extinguished agency that was devoted to architecture plans. It works quite
well even for larger formats (like blueprints) although in such cases we
have to acquire several A2 images.
It has 600 dpi resolution but only up to A3 formats, after which it only
copes to 400.
I think however that the software it is provided with the device (pixview)
hasn't enough features that allow a very good scanner adjustement, as it
only supports brithness and contrast.

Do someone has some experience with other software... We've tried acquiring
images through Photoshop but though it works, it only allows acquiring
images as bitmap and never as grey

thanks

francisco

____________________________
Francisco Barbedo
Arquivo Distrital do Porto (Porto State Archive)
Rua das Taipas, 90 | 4050-598 | Porto | Portugal
Tel: +351  223395170 | Fax: +351  223395179
email: fbarbedo@mail.telepac.pt
email2: francisco.barbedo@adporto.org

----- Original Message -----
From: James Stimpert <James.Stimpert@JHU.EDU>
To: <ARCHIVES@LISTSERV.MUOHIO.EDU>
Sent: Friday, December 08, 2000 7:26 PM
Subject: Re: Digital Scanners


> Having read these comments and others with great interest, I'll pass
> along my own impressions.  We have a Minolta PS3000, recently
> installed as a virtually new machine.  This model will scan at a
> maximum 400 dpi (also at 200 or 300 dpi), in three different modes:
> B/W, something in between, and "Photo" (the latter certainly resembles
> grayscale).  It will save images in one of three versions of
> compressed TIFF.  Just a few weeks ago I completed a rather exhaustive
> test, scanning samples of plain text pages, pages with intricate
> engraved lines, and high and low contrast photographs.  I scanned each
> example at all resolutions and settings, printed them on a 600 dpi
> laser printer, and placed them in a binder beside the thing for future
> reference.
>
> Based on this test (which I do not claim to be scientific, although I
> tried to limit variables and change only one at a time), the Photo
> mode produces a very high quality photocopy image of a photograph, but
> only at the 400 dpi setting.  I don't mean that the PS3000 will
> produce a publishable facsimile, but it does do an excellent job of
> producing a photocopy-quality image.  To test this perception, I also
> copied the same photos on a high quality photocopier in our library,
> that has a genuine grayscale photo mode.  While the photocopier
> version was better than the PS3000 version, the latter was, in my
> judgment, very good, and much better than I expected.  For intricate
> line drawings or engravings, the 400 dpi photo mode also worked best.
> For plain text pages of normal-size print, 200 dpi in B/W mode was
> adequate, while 300 dpi looked as good as any photocopier.
>
> I'm assuming the PS7000 is a more recent model.  If the PS7000 is
> newer, then Minolta seems to have gone backward, not forward.  The
> PS3000 will scan at 400 dpi max, while apparently the PS7000 will only
> scan at 300 dpi.  The PS3000 does have a "book correction mode" which
> works well to eliminate distortion due to curved pages in bound
> volumes, while the comment below says the PS7000 does not offer this.
> Both can scan documents, or facing pages, up to a total dimension of
> 11"x17".  The PS3000 manual claims it can achieve acceptable "depth of
> field" up to four inches above the copy deck, and this seems to be the
> case.
>
> While the three compressed TIFF modes vary in file size, there's no
> difference in the quality of the scan, and no difference in a file
> saved in these formats then re-opened.  The three TIFF modes are Group
> 3, Group 4, and something called JBIG.  Generally, JBIG gives slightly
> better file compression, if that's an issue, and I understand that
> Group 3 has been superseded by Group 4 (and maybe Group 4 has been
> superseded by JBIG).  I've also heard that not all programs can read
> JBIGs, but MS Photo Editor has no trouble with it, and that's about as
> "low-end" as you get in image editing software.
>
> I have it on good authority that Minolta is purposely remaining
> "behind the curve" in adding improvements to this line of scanner. I
> don't know whether this is because they have no direct competition
> with this type of device, or whether there's just not a large enough
> market to justify a major research-and-development effort.
>
> My conclusion is that you could certainly get a better scan from a
> $300 flatbed scanner (along with color) but for materials that are too
> fragile to go face down on a scanner or standard photocopier, the
> PS3000 is an acceptable substitute if you need its special
> capabilities.  If you never need to scan fragile volumes, get the
> flatbed scanner and don't give the PS3000 (or PS7000) a second
> thought.
>
> On Fri, 8 Dec 2000, Chuck Thomas wrote:
>
> > 1) it's incapable of color scanning, only grayscale at a max resolution
of
> > 300 ppi.
> >
> > 2) it CAN handle document larger than your typical flatbed scanner
> >
> > 3) the focus mechanism cannot handle rippled, curved paper surface very
> > well on flat pages. It will focus on one height, and cause some blurring
on
> > the indentations or "valleys" in rippled documents.
> >
> > 4) The illumination light on the PS7000 is VERY hot, and certainly
causes
> > more light damage to a document than does a traditional flatbed scanner.
I
> > joke with my students that we need to keep suntan oil close by when
using
> > the machine:) The tradeoff is that you can scan books that never before
> > could be scanned without spinal damage.
> >
> > Perhaps you could explain exactly what documents need to be scanned. If
> > flat paper document smaller than 11 x 17" (including photographs) are
what
> > you need to scan, then you can find an excellent color-capable flatbed
> > scanner for much less money.
> >
> > In our digital imaging lab here at the University of Minnesota, we have
not
> > one but two (liked the first one so much I bought another) Epson
Expression
> > 836 XL scanner, that do a remarkable job of producing photo-quality
scans.
>
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
> James Stimpert                       E-mail:    James.Stimpert@jhu.edu
> Archives (Arts and Sciences)
> MSE Library
> Johns Hopkins University             Voice:     (410) 516-8323
> 3400 North Charles Street
> Baltimore, MD  21218                 Fax:       (410) 516-7202
>
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>

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Problems?  Send e-mail to Robert F Schmidt <rschmidt@lib.muohio.edu>