A selection of three different image display formats are made available
for more detailed review of the historic maps in this collection. The images
were scanned at 24-bit color on an Ideal Magnum Wide Format FSCX050 scanner
at 300 dpi to create high resolution, uncompressed TIFF images. Early in
2004 with financial assistance from the Mary Ansari Endowment, the library
acquired an IDEAL/Contex Magnum XL 54" Plus Color Scanner . It scans at 24
bit color, up to 2400 dpi and will scan media up to 0.6 inches thick and up
to 54 inches wide. The scanner was manufactured in Denmark and distributed
in the U.S. by Ideal Scanners & Systems and is considered
to be one of the best front-loading large format scanners available at this time. This scanner is now the primary equipment for this project.
The JPEG files were derived from the TIFF file. The TIFF files were converted into the DjVu® format at a compression ratio of up to 220:1 using LizardTech's DjVu® compression software. The image files all live on the UNR Libraries' NAS server. Small representational images were loaded into the CONTENTdm™ digital project management software, then metadata was created for each image including web links to the three different image display formats. Of these, Djvu images are most easily displayed on desktop computers of limited capability or connectivity. A one-time download of the free DjVu browser plug-in is necessary and provided for this purpose. The metadata provides detailed information on the original and digital map. There are no copyright restrictions.
The JPEG 2000 format is used to present many oversized images in the maps collection. JPEG2000 is a published international ISO standard (ISO 15444). Based on newer wavelet compression technology, it offers both lossless and lossy compression and provides better image quality than JPG at smaller file sizes. More information about JPEG 2000 in CONTENTdm.