This Collection:
- View All
- About this Collection
- Digitizing the Collection
- Related Resources
- Project List and Image Sampler
- Rights And Restrictions
Browse By:
-
Creator/Related Names
(97) -
Subjects
(1206) -
Formats
(132)
More Resources
All images are digitized | All jpegs/tiffs display outside Library of Congress | View All
Digitizing the Collection
CSC of Chantilly, Virginia, scanned the slides, transparencies and negatives using an overhead capture Sinar 54 digital camera beginning in 2008. Each was scanned at a resolution of approximately 5,000 pixels on the long side with the short side scaled in proportion
Specifications for the Collection
Uncompressed Archival TIFF Images
Spatial Resolution: | A minimum of 5,000 pixels on the long side with the short side scaled in proportion for file names ending in u.tif (20-160 megabytes; average size: 50 mb.) |
Tonal (pixel depth) resolution: | 8 bits per pixel grayscale or 24 bits per pixel for color materials |
Image enhancement: | None. |
File format: | Tagged Image File Format (TIFF) ver. 6.0 |
Compression: | None |
Compressed Service Images
Spatial resolution: | 640 pixels on the long side with the short side scaled in proportion for file names ending r.jpg (15-100 kilobytes); 1024 pixels on the long side with the short side scaled in proportion for file names ending v.jpg (50-210 kilobytes) |
Tonal (pixel depth) resolution: | 8 bits per pixel |
Image enhancement: | Mild sharpening |
File format: | JPEG |
Compression: | Compressed to yield an average compression ratio of 10:1 |
Thumbnail Images
Spatial Resolution: | 150 pixels on the long side with the short side scaled in proportion for file names ending in t.gif (approximately 10 kilobytes) |
Tonal (pixel depth) resolution: | 8 bits per pixel |
Image enhancement: | Mild sharpening |
File format: | Archived copy: TIFF - Tagged Image File
Format Online copy: GIF - Graphics Interchange Format |
Compression: | Archived copy: Uncompressed Online copy: Compression native to the GIF format |