The baseball cards are one of the first American Memory pictorial collections whose images have been produced by direct capture with a digital camera at high levels of spatial resolution. Most of the collections of photographs and prints for which production began prior to 1998 were produced via photographic intermediates and, with the exception of the panoramic photographs, at lower levels of resolution.
The Library's baseball cards have great value as cultural artifacts. The Library has carefully conserved this collection and will retain the originals. Although the Library does not call the archival or master digital images of the baseball cards "preservation copies," these images will play the same role vis-a-vis the original as have copies made on photographic film in the past. We hope that our online users can use these images to conduct research that requires a clear view of very small features of the original, to enliven student presentations, or to illustrate a book (copyright permitting). We will be interested to hear if users are able to download the high-resolution archival versions of the images and use them as a source for printing or projection.
The front of every card was scanned; backs of cards were scanned only when printed information was present. The online presentation of the baseball cards follows the pattern used in other American Memory pictorial collections. The bibliographic record is accompanied by a thumbnail image (or two, if the back was scanned), each of which provides access to a compressed service (or reference) image and the uncompressed archival (or master) image.
The digital images in the baseball card collection were produced by JJT Incorporated of Austin, Texas, using their new MARC II digital camera. This overhead device permits the cards to be safely placed on a copy stand and the camera's depth of field means that cards showing slight curvature need not be pressed flat for scanning. The images were initially captured using a 3500x3500 pixel matrix at 36 bits-per-pixel. Image processing is then executed at 48-bits-per-pixel. For the archival or master image as saved, the spatial resolution was reduced to 3000 pixels on the long side (with the short side scaled in proportion) and the tonal resolution reduced to 24 bits per pixel. JJT's post- processing step also created the two derivative images that complete the set of three delivered to the Library.
Specifications For This Collection
|Spatial resolution:||About 3,000 pixels on the long side with the short side scaled in proportion. This spatial resolution was employed regardless of the size of the original cards, which range from about 1 to 8 inches. Thus, resolution in terms of dots-per- inch varies throughout the collection.|
|Tonal (pixel depth) resolution:||24 bits per pixel (RGB color) |
|Image enhancement:||No sharpening other than that inherent in the camera itself. |
|File format:||Tagged Image File Format (TIFF) ver. 6.0|
|Compressed Service Images|
|Spatial resolution:||About 640 pixels on the long side with the short side scaled in proportion.|
|Tonal (pixel depth) resolution:||24 bits per pixel|
|Image enhancement:||Mild sharpening. In some cases, the uncompressed images were blurred before rescaling and sharpening in order to reduce the moiré patterns that result when printed halftones are scanned.|
|File format:||JFIF (JPEG File Interchange Format)|
|Compression:||JPEG at a quality setting that yields an average compression of 15:1.|
|Spatial resolution:||About 150 pixels on the long side with the short side scaled in proportion.|
|Tonal (pixel depth) resolution:||8 bits-per-pixel; palettes optimized (adaptive palettes) for each image.|
Format (TIFF)Tagged Image File
GIF (Graphics Interchange Format) format
compression native to the GIF format.