Digitization Guidelines
* work in progress -- Andreas Gros 17:34, 17 March 2008 (CET)
In the following you will soon find a relevant subset of the DFG guidelines for digitization[1] and, in addition, a description of a workflow for digitizing and submitting digital documents for digital collections maintained by the MPDL.
Scanning[edit]
Resolution and Image Quality[edit]
For scanning greyscale or colored prints, a minimum resolution of 300 dpi is suggested. Documents containing handwriting or maps with fine lines and small descriptions might require a scan resolution of up to 400 dpi. For generating bitonal scans, 600 dpi are requested.
Color depth[edit]
Bitonal scans (b/w) are generated with a color depth of 1 level (1 bit) per pixel. Greyscale images are digitized with 256 levels (8 bit = 1 byte) per pixel. Color images use 3 color channels (red, green, blue) with 1 byte per channel (= 3 byte = 24 bit) per pixel, enabling 256 x 256 x 256 = 16.7 million colors per pixel. 24 bit provide a sufficiently high color depth for color scans. Scanning with 48 bit color depth makes sense only in few cases where images need to be corrected or reworked after the scanning process.
File formats[edit]
Master images of greyscale or color images should be stored in "TIFF uncompressed". For bitonale images TIFF with group 4 compression can be used. In the future JPEG2000 could be used as an alternative to "TIFF uncompressed". Unfortunately, currently there are not enough software tools available to make JPEG2000 a feasible tool for the archiving of master images.
Fulltext digitization[edit]
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Metadata requirements[edit]
* to be continued