Controlled Digital Lending
What is CDL?
Controlled Digital Lending (CDL) is a model of peer to peer digitisation and lending of copyrighted works between libraries developed in the US. Libraries digitise works held in their collections and “lend” them through digital sharing with end-users of other libraries. Using digital rights management (DRM), the “lending” library will ensure that the requester has access for a time limited period analogous with the traditional loaning of printed materials.
CDL was developed utilising the principles of copyright “fair use” under US copyright law. It should be noted, that CDL remains controversial and is opposed by rights holders. Adoption in the UK is limited at the current time.
“Through CDL, libraries use technical controls to ensure a consistent “owned-to-loaned” ratio, meaning the library circulates the exact number of copies of a specific title it owns, regardless of format, putting controls in place to prevent users from redistributing or copying the digitized version. When CDL is appropriately tailored to reflect print book market conditions and controls are properly implemented, CDL may be permissible under existing copyright law. CDL is not intended to act as a substitute for existing electronic licensing services offered by publishers. Indeed, one significant advantage of CDL is addressing the “Twentieth Century Problem” of older books still under copyright but unlikely ever to be offered digitally by commercial services.”
Extract from the Controlled Digital Lending website