14. Project findings
The findings of the Manuscript Digitization Demonstration
Project may be summarized as follows:
- Tonal (grayscale and color) images are necessary for
preservation-quality reproduction of many manuscripts.
- A spatial resolution of 300 dpi for tonal images is
sufficient to capture all information in twentieth
century materials like typescripts.
- Some documents benefit from color reproduction but
ambiguity remains about when color reproduction is
necessary to serve researchers.
- For preservation-quality images of routine
documents--especially in the setting of a high-volume
digitization effort--the benefit of reduced file
size resulting from the modest application of lossy
compression (at around 10:1 for JPEG) can be argued to outweigh the cost
of the slight image degradation that results.
- Access images can be produced by reprocessing the
preservation-quality images.
- If end users are to be provided with easy navigation in
the World Wide Web, "browser-capable" tonal
display-access images must be provided.
- If end users are to be provided with clean printouts from
a laser printer, separate binary print-access images
should be considered; laser printouts from the reduced-size tonal
display-access images will be less legible.
- Objective tools for quality review are needed.
The Library welcomes comments on the Manuscript Digitization
Demonstration Project, especially responses from researchers who
use the testbed images. Comments may be sent to ndlpcoll@loc.gov.
The Library looks forward to carrying out additional projects
that will further refine the issues described here and hopes that
others will also continue to investigate these and related
matters. The Library's staff stand ready to consult with
interested parties undertaking such investigations.
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