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Building the Digital Collections
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The Atlantic World: America and the Netherlands digital collection currently comprises multiple formats from throughout the collections of the Library of Congress and its partner institutions. The collection includes printed matter in Dutch and English, some with foldout illustrations or maps; handwritten manuscript material; pictorial material (mainly in watercolors); and bound and unbound cartographic materials. The variety of original formats required specialized digitization for each format and scanning and post-processing contributions from many members of the Digital Conversion Group. The production of this digital collection proceeded under format digitization standards as developed by the Library of Congress's American Memory program. Specific scanning information is provided for each format.
Materials held in Dutch institutions were digitized by the National Library of the Netherlands. Although several items in this collection are found in other cooperative Dutch institutions, the Web site, metadata, and digital image files are stored at the National Library of the Netherlands and are under its management.
All online items are described and searchable individually in a bibliographic record database using MARC and non-MARC record cataloging. The mechanism for the technical aspects of the cooperation between the Library of Congress and National Library of the Netherlands is a "metadata exchange approach" whereby metadata for materials in both institutions exist on both sites and point to image presentations that reside only on the respective institution sites. The image presentations are linked through persistent URLs provided in the metadata.
Specifications for Library of Congress Digitization
Printed materials in The Atlantic World: America and the Netherlands were digitized on-site by the Library═s Information Technology Services (ITS) Digital Scan Center. Each item was reproduced as a facsimile page image. In order to preserve the original items, bound works were scanned in their bindings, one page at a time.
General Collections: Selected items contain textual pages (with typography and line art) were scanned as 300 dots-per-inch (dpi) bitonal images in the TIFF format and converted using ITU Group IV compression. Reference images in GIF format were created for quick online access. These images were derived from the archive files during the post-processing phase of production.
Rare Books and Special Collections: Selected items include printed halftone illustrations, finely detailed line drawings, or pages with significant color, including book covers. All pages were digitized as 300 dpi, 24-bit RGB color images to capture the physical nature and age of the material. Reference images in GIF format and higher quality images in JPEG format were created for quick online access. These images were derived from the archive files during the post-processing phase of production.
Several books in the collection also contain oversized foldout illustrations or maps. These pages were treated and prepared for scanning by the Library═s Conservation Division, procedures that required them to be unfolded and flattened. One book contained an image of a map that was subsequently compressed using the Multi-Resolution Seamless Image Database (MrSID) format, frequently used for stand-alone cartographic material. Although MrSID is a "lossy" compressor, the images were compressed at a ratio of 22:1 without experiencing any loss of information. This software integrates multiple resolutions of an image into a single file, which enables Internet users to zoom in for greater detail. These images are integrated with other page image formats to create a complete sequence of pages for a particular item. LizardTech donated the license for the compression software.
These print materials are described in the database using pre-existing and updated MARC-format catalog records.
Manuscript materials in The Atlantic World: America and the Netherlands were digitized on-site by the Library's ITS Digital Scan Center. All items digitized have an original translation into English as a separate, associated document created approximately one hundred years after the Dutch original. Each item was reproduced as a facsimile page image. In order to preserve the originals, bound works were scanned in their bindings, one page at a time.
These handwritten materials were scanned in 24-bit RGB color in order to capture and display a wide range of tonal variations, from those in the document paper to diverse qualities of pencil and ink.
Reference images in GIF format and higher quality images in JPEG format were created for quick online access. These images were derived from the archive files during the post-processing phase of production.
Title constructs were created by specialists in the European Division. Individual item-level descriptions and records were created for bibliographic image displays. Data is stored as non-MARC records and exported during data delivery. Each record has an item number, description of content, and date.
Cartographic materials from the Library's collections were created by Geography and Map Division staff who scanned original maps in 24-bit RGB color. Each raster image was produced by scanning the item at a resolution of 300 dpi and converting to TIFF format.
The TIFF files were compressed, using MrSID, a wavelet-based image compressing software.
These items are described in the database using pre-existing and updated MARC-format catalog records.
Specifications for the National Library of the Netherlands Digitization:
For technical information on digital items owned by the National Library of the Netherlands for the Memory of the Netherlands site, please contact:
The Memory of the Netherlands Project Office
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