The Collaborative Digitization Program has developed a set of Imaging Best Practices http://www.bcr.org/cdp/best/comments.html. They are no longer looking for feeback; but, their knowledge base is certainly interesting.
Here is how they describe their initiative...
"It is intended to serve as a guide for practitioners in cultural heritage institutions that seek to create digital images from physical objects. Originally published by the Colorado Digitization Program in 2003 as the Western States Digital Imaging Best Practices, this updated version reflects the many changes that have occurred in the digitization field during the last five years."
