What is an item, or a document?
An item, or a document, refers to an intellectual "thing" which cannot be reduced (without destruction).
For example, a letter is a document. If a page of the letter is removed, the letter is partially destroyed. Hence, a page is not a document unless that is the full extent of the item.
For a second example, a single image which stands on its own, is a document, or an item. If, however, the image is the 2nd or third page of a series of images of a musical score, then this image is not, by itself, a document. It is a portion of a document.
For a third example, an audio file which is a single segment of a performance is not a document; the compilation of all the audio files in the correct order, represents the intellectual whole. This is then considered an item, or a document.
It is our policy to always create descriptive metadata for digitized content at the item (or document) level. (I'm using these two terms interchangeably).
While we may choose to create page-level descriptive metadata in certain circumstances to grant greater searchability and accessibility, this is not standard policy.