Building the Digital Collection |
In the summer of 2000, JJT, Inc., of Austin, Texas, scanned Ansel Adams's Manzanar black-and white photographs. They used an overhead MARC II digital camera to scan both the 209 gelatin silver prints (in various sizes measuring up to 10x14 inches) and the 242 acetate and nitrate negatives (measuring either 4x5 or 5x7 inches). The images were captured in grayscale at a spatial resolution of approximately 10,000 pixels on the long side and a tonal resolution of 16 bits per pixel to help the Library begin to explore issues related to preservation-quality digital surrogates for photographs. The Library is considering the extent to which these files can be used to generate high-quality reproductions in a variety of media. With today's resources, these very high resolution images require significantly increased costs, particularly in time spent capturing, inspecting, and loading the files. For most collections in the Prints and Photographs Division, online digital images, even at lower resolutions, play an important preservation role as surrogates that reduce handling of the original pictures.
Digital images of each print and its corresponding negative display side by side in each bibliographic record to facilitate comparison. The print is on the left, and the negative is on the right. When Adams provided only a print (two cases), or only a negative (thirty-six cases), a single image displays.
Although Adams mounted the prints on large boards, the digital images show only the photograph and Adams's signature when present. A third digital image showing the whole mount documents the eight mounts that have a printed label, which may indicate that the photograph was included in an exhibition.
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Negative | Print with labeled mount |
| LOT 10479-1, no. 12 LC-A35-4-M-X | ||
| Yuchi Harata, Manzanar Relocation Center. Photograph by Ansel Adams, 1943. | ||
Specifications for the collection:
| Uncompressed Archival TIFF Images | |
| Spatial resolution: | 5,000 pixels on the long side with the short side scaled in proportion for file names ending in u.tif (17-20 megabytes) |
| Tonal (pixel depth) resolution: | 8 bits per pixel (grayscale) |
| Image enhancement: | None |
| File format: | Tagged Image File Format (TIFF) ver. 6.0 |
| Compression: | None |
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Highest Resolution TIFF Images |
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Spatial resolution: |
10,000 pixels on the long side with the short side scaled in proportion (approximately 130 megabytes) |
| Tonal (pixel depth) resolution: | 16 bits per pixel (grayscale). Note: Some older versions of image viewers and editing software cannot handle 16 bit images. |
| Image enhancement: | None |
| File format: | Tagged Image File Format (TIFF) ver. 6.0 |
| Compression: | None |
| Compressed Service JPEG Images | |
| Spatial resolution: |
640 pixels on the long side with the short side scaled in proportion for file names ending r.jpg (40-50 kilobytes); 1024 pixels on the long side with the short side scaled in proportion for file names ending v.jpg (90-100 kilobytes) |
| Tonal (pixel depth) resolution: | 8 bits per pixel (grayscale) |
| Image enhancement: | Mild sharpening |
| File format: | JPEG |
| Compression: | Compressed to yield an average compression ratio of 10:1 |
| Thumbnail GIF Images | |
| Spatial resolution: | 150 pixels on the long side with the short side scaled in proportion for file names ending in t.tif and t.gif (approximately 20 kilobytes) |
| Tonal (pixel depth) resolution: | 8 bits per pixel (grayscale) |
| 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 | |
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Library
of Congress( July 14, 2008 )