Scanning the Paper Manuscripts
The paper manuscripts in Selections from the Naxi Manuscript Collection were digitized by the Digital Scan Center, of the Library’s Information Technology Services Directorate. The image capture also took place at the Library of Congress. In order to preserve the originals, bound works were scanned face-up in their bindings, one page at a time. The master, or archival version of the pages (containing typography and line art), is a 300-dots-per-inch (dpi) color image in the TIFF format.
The browser-display images for the catalog were generated from the master TIFF files in the JPEG format, using an Image Alchemy script.
Scanning the “Journey to Heaven” Scroll
The 39½-foot long scroll “Journey to Heaven,” was scanned in sections at the Digital Scan Center with assistance from conservationist Jesse Munn.
The images were converted to MrSid images by Library staff. MrSid—a multi-resolution seamless image database—uses a wavelet compression technology made available to the Library of Congress by LizardTech of Seattle, Washington. This software for the storage and retrieval of large digital images is derived from the research efforts of Los Alamos National Laboratory, New Mexico. In contrast to other compression software that relies on tiling, MrSID gets all its sharp resolution from within a single compressed image and does not require any special hardware. File size does not matter. MrSID allows immediate access to any part of an image, of any size, at any resolution.
The unique feature of MrSID is its ability to decompress only that portion of the image requested by the user. The compression ratio is approximately 22:1 depending on image content and color depth. Because fast, easy access is provided through networks and the Internet to vast amounts of geographic information, MrSID is ideal for viewing maps, orthophotos, terrain models, and satellite data.
Scanning the Annotated Catalog
The annotated catalog to the Naxi Manuscript Collection, created by Dr. Zhu Baotian, was also digitized by the Library of Congress’s Digital Scan Center. The master, or archival version of the pages (containing typography and line art), is a 300-dots-per-inch (dpi) bitonal image in the TIFF format, with ITU Group IV compression.
The browser-display images for the catalog were generated, from the master TIFF files, in the JPEG format, using an Image Alchemy script.
The single-sheet manuscripts are portions of larger multi-page manuscripts whose other pages have been lost. As a result, the standard bibliographic information Professor Zhu culled from the intact multi-page manuscripts was unattainable. In order to complete the catalog, Professor Zhu substituted complete catalog records for these single-sheet items with a photocopy of the single-sheet along with its Zhu Number and, if available, its other classification numbers. As digitizing these photocopies would have resulted in poor quality images, they were not scanned.