Message-Id: <200004061313.GAA18966@dns.ccit.arizona.edu> Date: Thu, 6 Apr 2000 08:58:59 -0400 From: "LeMar,Greg" <mailto:lemarg@OCLC.ORG> Subject: Re: Experiences with digitizing material not suitable for aflatbe To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU
<pre>
Still more. Many solutions, but still no mention of an archival
intermediate.
-----Original Message-----
From: Andrew Stawowczyk Long [mailto:mailto:anlong@NLA.GOV.AU]
Sent: Thursday, April 06, 2000 12:39 AM
To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU
Subject: Re: Experiences with digitizing material not suitable for
aflatbed
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Mark,
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.
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 during 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 need 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 best results.
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.
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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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>
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</pre>
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