Scanning Criteria
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Scan documents at 600 ppi resolution and 24-bit color. |
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Scan documents at 100 percent of their original size. |
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Save documents as uncompressed TIFF files (most page images will range in size from 70MB to 130MB). |
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Scan each image with a Kodak Q-13 color separation guide and ruler. Make certain to align the ruler edge with the right edge or bottom of the page of the document. Place the color guide/rule to minimize blank space. Place the ruler next to the document itself. The scan should include at least part of all color boxes. See below for examples: |
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Scan blank intervening pages. Do not scan trailing blank pages. (If a three-page document has writing on page 1 and page 2, but not on 3, scan only pages 1 and 2; if a four-page document has writing on page 1 and page 3, scan page 2, but not page 4). |
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Scan envelopes, file notes, etc. Scan these as additional pages with the associated documents. |
Metadata—File Information to Capture
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Please include the following metadata:
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If using Photoshop 7.0 or Photoshop CS2, please capture the preceding information in the “File Info”: On the General or Description Tab Caption or Description—enter the document’s descriptive name Caption Author or Description Writer—enter the name of the scanning technician On the Origin Tab Date Created—enter using the automated “Today” button City—enter the city location of the institution housing the document State—using the two-letter U.S. postal service abbreviation, enter the state location of the institution housing the document Credit—enter the name of the institution housing the document Source—enter the name of the collection in which the document is located Note: Please be consistent across files in the way in which you enter the data. |
Delivery of Electronic Images
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Transfer the images to CD-ROM or DVD-R disc. |
Supporters of the Papers of Abraham Lincoln may wonder why the project seeks to preserve and deliver color images of manuscript material. After all, the value of these manuscripts is in the words themselves, right? There are three fundamental reasons why the Papers of Abraham Lincoln has chosen to capture document images on color microfilm and to deliver color rather than grayscale digital images in the comprehensive electronic edition of the Papers of Abraham Lincoln.
First, and most importantly, color enhances the accuracy of the editorial
process. Color improves the contrast and readability of manuscript materials.
Capturing the color of the aged paper and the ink makes strikeouts easier to
read and provides important clues about authorship, how the document was
created, and the distinctions between purposeful pen marks and stray marks or
other blemishes.
Second, color preserves colorful
attributes of manuscript materials themselves, from the blue
paper common for letters written in Lincoln’s time (which has come to be known
as “Lincoln blue” by
manuscript collectors) to color inks, stamps, and even color letterhead and
patriotic envelopes and
stationery.
Third, color enhances the aesthetic connection between the reader and the original documents. Users of computer resources of all types increasingly expect and demand high-quality color images, and the advent of sharper monitors and low-cost color printers makes such images a requirement for a modern edition.
The Papers of Abraham Lincoln captures digital images of original documents at
600 ppi (or pixels-per-inch). Although there are a wide range of opinions and
practices when it comes to the digitization of original manuscript material, the
Papers of Abraham Lincoln has elected to create master digital images at a very
high resolution to minimize the need for future re-digitization and to provide
the maximum data for the preparation of color microfilm images from the color
digital images. The resulting master files are very large but capture small text
very legibly, improve the quality of derivative images, and can produce a
high-quality publication if necessary or desirable.
In choosing 600 ppi, the Papers of
Abraham Lincoln follows best-practice guidelines from several digital imaging
libraries or projects. The University of Virginia Libraries recommends 600 ppi,
saved as uncompressed TIFFs, for preservation quality images of books and
manuscripts (http://www.lib.virginia.edu/digital/reports/uva_digitization_guidelines.html).
Likewise, the Kentuckiana Digital Library notes that “There is a degree of
consensus to establish 600dpi as the preferred resolution level for capture of
any document size and type.” That institution’s guidelines recommend 600 ppi
where the technological and human resources are available (http://kdl.kyvl.org/guidelines.html#five).
Similarly, Daniel J. Cohen and Roy Rosenzweig recommend that “digital masters
should be uncompressed TIFFs... a dynamic range of ... at least 24 bits for
color images, and scanned at 300 to 600 dpi. Scan your images at the highest
possible quality....” (Cohen and Rosenzweig, Digital History: A Guide to
Gathering, Preserving, and Presenting the Past on the Web [Philadelphia:
University of Pennsylvania Press, 2006], 99-100).
A report on a national digitization
plan published by the Government Printing Office in February 2006 recommended at
least 400 ppi, 24-bit color for reflective material (http://origin.www.gpoaccess.gov/legacy/registry/fdsysspec_converted_content3.3.pdf;
see also
http://www.archives.gov/preservation/technical/guidelines.pdf).
A resolution of 600 ppi allows for
the creation of substantially better derivative PDF or DJVU files than is possible with
300 ppi images. Because we use the derivative images for transcription, referring to
the master TIFFs only when necessary, the quality of the digital derivatives is
an important part of our workflow. The quality of a print of a derivative file created
from a 600-ppi master is also significantly better than the print of a
derivative from
a 300-ppi master.