Open access (OA) refers to freely available, digital, online information. Open access scholarly literature is free of charge and often carries less restrictive copyright and licensing barriers than traditionally published works, for both the users and the authors.
While some OA publishers require authors to pay page charges to help defray the cost of publishing, OA is not vanity publishing or self-publishing since legitimate OA publishers still submit authors to the same rigors of peer review as traditional academic publishers. For more information, see:
Green OA publishing refers to the self-archiving of published or pre-publication works for free public use. Authors provide access to preprints or post-prints (with publisher permission) in an institutional or disciplinary archive such as:
Gold OA publishing refers to works published in an open access journal and accessed via the journal or publisher's website. Examples of Gold OA include:
Image: Opensource.com, http://tinyurl.com/l7y66vo
Copied, with changes and permission, from the "Open Access Publishing" guide, created by the Gail Steinhart and Jeremy Cusker at Cornell University.