Collections frequently contain copies of material present in the collection in its original form, copies of material held by other institutions, and copies of material for which the location of the original is not known. The decision to retain or discard these copies depends on the nature of the documents and the circumstances of the collection.
True duplicates should be removed if they are easily identified or if a review of duplicates would result in a great volume of discards. For less granular processing levels, identify duplicates only if there is such a significant quantity that storage concerns outweigh processing expediency concerns.
Weeded duplicates should be put aside until the processing project is complete. Duplicate material can then be referred to the curator, who may or may not wish to examine it before giving approval to discard.
Item-level processing of duplicates
Retain no more than 2-3 copies (i.e., original and best copies) of any item in the collection.
When checking multiple copies for (possible) minor variations is simply too time consuming, retain all copies.
In the past, material from one Beinecke collection were sometimes photocopied and filed into related collections in order to facilitate research access to materials related by topic. The library also sometimes provided donors with copies of material that they donated, and these copies were then given to the library as part of later accessions. Once the presence of the originals is verified, these can usually be discarded.
Creators of collections often collect copies of material from a variety of sources in the course of their own research and in pursuit of their own interests, and these are usually kept and considered an organic part of the collection.
In other cases, copies were given to the library in lieu of the originals, as in the case of personal correspondence from a prominent individual that the recipient did not want to part with. In most cases, this material is retained, but in some cases (for instance, a large volume of copies for which the originals are known to be available in another institution) the library may decide to discard this material.
In the absence of an original source document that can be used for verification, transcripts should be considered original documents. Transcripts should be so noted in the box and folder list to avoid confusion about the location of the original document.
If a folder contains both an original document and a library- or dealer-supplied transcript, the transcript usually is not kept unless the original is extremely difficult to read. If the archivist decides that the information on the transcript is worth retaining, s/he should consider photocopying it onto acid-free paper and then discarding it.
Transcripts made by or for the creator of the collection are usually retained, filed after the original items.