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- Files should use color rather than grayscale when color is an integral part of the original object, and any compression applied to the file should be lossless. Document Services uses LZW compression which is lossless.
- Some file formats discard redundant information to reduce the file’s size, a process known as compression. Best practices suggest saving master digital images in an uncompressed file format, such as TIFF.
The table below contains the minimums recommendations for digitization sorted by material type.
Type | Resolution | Bit Depth | Color Mode | Archival File Format | |||||
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Multi-page text documents B&W | 400 dpi | 1 bit | Bitmap | TIFF | |||||
Image - photo, illustrations, artwork |
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Multi-page text documents Color | 400 dpi | 24 bit | RGB | TIFF | |||||
Multi-page text documents mixed grayscale color | 400 dpi | 8 bit Grayscale | Gray | TIFF | Maps, oversized items |
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transparencies, slides |
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Multi-page text documents Color |
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Image - photo, illustrations, artwork | 400 dpi | 24 bit | RGB | TIFF | |||||
Maps, oversized items | 400 dpi | 24 bit | RGB | TIFF | Multi-page text documents mixed grayscale color |
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OCA (Internet Archive) projects - multi-page text documents | 300 dpi | 24 bit | RGB | JPEG2000 | |||||
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Note regarding Digital Audio:
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