Standards for imaging: The PDHC guidelines for imaging are based on the California Digital Library Guidelines for Imaging which “draws substantially on the Federal Agencies Digitization Initiative (FADGI) – Still Image Working Group’s Technical Guidelines for Digitizing Cultural Heritage Materials: Creation of Raster Image Master Files.” While a complete version of the PDHC imaging guidelines are available PDHC-Revised-Technical-Standards (1) a frequently consulted subset is provided below.
- Original photographs and graphic images 8″ x 10″ or smaller should be scanned so that the resulting image contains 4,000 pixels across the long dimension of the image area (excluding borders and mounts). Generally this means scanning at between 300 and 800 pixels per inch. The image should be saved as a TIFF file with no corrections.
- Institutions may upload earlier scanned images which were scanned according to the standards of the time at which they were scanned.
- Original text items will be scanned at 600 dpi and saved as TIFF files with no corrections. EXCEPTION: If the smallest type on the page is 24 points high or larger (for example, posters with large type), scan at 300 pixels per inch.
Quality Assurance: Quality assurance training will follow guidelines established in the Cornell Digital tutorial, Moving Theory Into Practice: Digital Imaging for Libraries and Archives. http://www.library.cornell.edu/preservation/tutorial/quality/quality-03.html
Preservation and migration: Each institution is responsible for maintaining the original items and the digital copy that lives at its institution in accordance with best practices. The manager of the CONTENTdm database is responsible for preserving the copy that lives on the PDHC database and for ensuring its continued accessibility through any necessary format changes or migrations.
Quality control for metadata: Quality control is established in a hierarchy of workflow as agreed upon by the participating institutions. The parameters are set by the administrative system design of CONTENTdm. The software allows for object metadata to be input, edited, and uploaded first and then sent for approval by the designated administrator. Dan McLaughlin of PPL is the current administrator for all objects and his role is to examine uploaded object metadata and provide corrections or request resubmission.