Message-Id: <200004080330.UAA09528@dns.ccit.arizona.edu> Date: Fri, 7 Apr 2000 20:27:13 -0700 From: Robert McGeary <mailto:robmac@REMNET.COM> Subject: Re: Experiences with digitizing material not suitable for aflatbed To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU
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Andrew Stawowczyk Long wrote:
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> Mark,
>
> Here in the National Library of Australia we did couple of projects that involved digitising at high resolution. We a
med at 300dpi at 100%. As we were working with unique, fragile and oversized material
> (rare maps, manuscripts) we couldn't use a flat bed scanner. Instead we worked with high-end digital scanning back co
bined with a Sinar large format camera. It worked extremely well for most items
> achieving the required resolution. The back was Phase One with 8,400 x 6,000 pixel resolution and 36-bit internal colo
r depth. Some of the maps we needed to shoot in tiles, later stitching them together
> on a computer to get 300dpi resolution. It can be avoided by using a new Phase One back called Power FX with resoluti
n exceeding 12,000 x 10,000 pixels.
>
> Some of the important things to be aware of:
>
> - Required light levels are very high - can be dangerous from the archival point of view.
> - Power conditioners (stabilisers) have to be used for lights as light levels have to be maintained very acurately dur
ng 5-20 minutes of exposure.
> - High resolution lenses (designed for digital capture) have to be used.
> - Powerful computers with large hard disks and a lot of RAM (500Mb - 1Gb) are needed.
> - Scanning back and computers need to be colour calibrated to a known standard (we use CIE D65) and colour profiles ne
d to be used (ICC) to maintain colour accuracy throughout the system chain.
> - It is a common practice to capture at 36 or 48-bit colour depth and then reduce it to 24-bit for storage. It gives
est results.
>
> Also, we evaluated an option for capturing images on film (4" x 5" transparencies) and scanning them later on but the
esults were not satisfactory. It was due partially to the much lower dynamic range of
> a photographic film than those of digital devices (typically for film it is 6 f-stops and at least 11 f-stops for high
quality digital devices). Also, it is much more labor intensive and more expensive.
>
> I hope that'll help. Let me know if you need more info.
>
> Regards
>
> Andrew Stawowczyk Long
> Public Affairs Officer
> National Library of Australia
> Phone: +61 2 6262 1382
> EMAIL: mailto:anlong@nla.gov.au
>
> >
> > >>> Mark Jordan <mailto:mjordan@SFU.CA> 04/06/00 11:02 >>>
> > Hi,
> >
> > We've been doing some research on the costs of equipment suitable for
> > digitizing material such as books, oversized posters, drawings, etc. that
> > we wouldn't want to (say pages from a rare and fragile book) or couldn't
> > (because of size) scan with a flatbed, even one with a 12x17" platten. To
> > get 24-bit color at a 300 dpi or higher, we'd have to spend quite a bit of
> > money.
> >
> > Does anyone have any experience with alternative methods of digitizing
> > largish-size material not suitable for scanning with flatbeds into 24-bit
> > color, high resolution images? For example, could photograph the items,
> > create high-quality prints or slides, and then scan the photo? Or is this
> > kind of method just not practical?
> >
> > Thanks for sharing any experiences you may have had with this kind of
> > material,
> >
> > Mark
> >
> > Mark Jordan
> > Librarian / Analyst, Systems Division
> > W.A.C. Bennett Library, Simon Fraser University
> > Burnaby, British Columbia, V5A 1S6, Canada
> > Email mailto:mjordan@sfu.ca / Phone (604) 291 5753 / Fax (604) 291 3023
>
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> Content-Transfer-Encoding: 7bit
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> <!doctype html public "-//w3c//dtd html 4.0 transitional//en">
> <html>
> Mark,
> <p>Here in the National Library of Australia we did couple of projects
> that involved digitising at high resolution. We aimed at 300dpi at
> 100%. As we were working with unique, fragile and oversized material
> (rare maps, manuscripts) we couldn't use a flat bed scanner. Instead
> we worked with high-end digital scanning back combined with a Sinar large
> format camera. It worked extremely well for most items achieving the required
> resolution. The back was Phase One with 8,400 x 6,000 pixel resolution
> and 36-bit internal colour depth. Some of the maps we needed to shoot
> in tiles, later stitching them together on a computer to get 300dpi resolution.
> It can be avoided by using a new Phase One back called Power FX with resolution
> exceeding 12,000 x 10,000 pixels.
> <p>Some of the important things to be aware of:
> <p>- Required light levels are very high - can be dangerous from the archival
> point of view.
> <br>- Power conditioners (stabilisers) have to be used for lights as light
> levels have to be maintained very acurately during 5-20 minutes of exposure.
> <br>- High resolution lenses (designed for digital capture) have to be
> used.
> <br>- Powerful computers with large hard disks and a lot of RAM (500Mb
> - 1Gb) are needed.
> <br>- Scanning back and computers need to be colour calibrated to a known
> standard (we use CIE D65) and colour profiles need to be used (ICC) to
> maintain colour accuracy throughout the system chain.
> <br>- It is a common practice to capture at 36 or 48-bit colour depth and
> then reduce it to 24-bit for storage. It gives best results.
> <p>Also, we evaluated an option for capturing images on film (4" x 5" transparencies)
> and scanning them later on but the results were not satisfactory.
> It was due partially to the much lower dynamic range of a photographic
> film than those of digital devices (typically for film it is 6 f-stops
> and at least 11 f-stops for high quality digital devices). Also, it is
> much more labor intensive and more expensive.
> <p>I hope that'll help. Let me know if you need more info.
> <p>Regards
> <p>Andrew Stawowczyk Long
> <br>Public Affairs Officer
> <br>National Library of Australia
> <br>Phone: +61 2 6262 1382
> <br>EMAIL: mailto:anlong@nla.gov.au
> <br><a href="http://timeframes.natlib.govt.nz/"></a>
> <blockquote TYPE=CITE>
> <br>>>> Mark Jordan <mailto:mjordan@SFU.CA> 04/06/00 11:02 >>>
> <br>Hi,
> <p>We've been doing some research on the costs of equipment suitable for
> <br>digitizing material such as books, oversized posters, drawings, etc.
> that
> <br>we wouldn't want to (say pages from a rare and fragile book) or couldn't
> <br>(because of size) scan with a flatbed, even one with a 12x17" platten.
> To
> <br>get 24-bit color at a 300 dpi or higher, we'd have to spend quite a
> bit of
> <br>money.
> <p>Does anyone have any experience with alternative methods of digitizing
> <br>largish-size material not suitable for scanning with flatbeds into
> 24-bit
> <br>color, high resolution images? For example, could photograph the items,
> <br>create high-quality prints or slides, and then scan the photo? Or is
> this
> <br>kind of method just not practical?
> <p>Thanks for sharing any experiences you may have had with this kind of
> <br>material,
> <p>Mark
> <p>Mark Jordan
> <br>Librarian / Analyst, Systems Division
> <br>W.A.C. Bennett Library, Simon Fraser University
> <br>Burnaby, British Columbia, V5A 1S6, Canada
> <br>Email mailto:mjordan@sfu.ca / Phone (604) 291 5753 / Fax (604) 291 3023</blockquote>
> </html>
>
> --------------201CB6430B73D0AB615741D5--
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