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Open Access

Open access refers to the free, immediate, online availability of research outputs such as publications and data. There are no financial, legal or technical barriers to accessing it - anyone can read, download, copy, distribute, print, search for and search within the information, or use it in education or in any other way within the licences granted.

Open access increases the visibility and reuse of academic research results, therefore leads to increased citations and impact.

It also helps in knowledge management and evaluation, facilitates archiving and long-term storage of digital content. It is an effective tool for promoting the researcher. 

Green Open Access

Full texts of scientific publications are deposited by the author in a trusted repository (in accordance with the publisher's contract). When an author publishes their text in a journal with a traditional subscription-based publishing model, usually when entering into a contract with the publisher, the author waives some or all of their copyrights to the article. Publishers have a specific OA policy according to which the author can self-distribute his or her work. The most common is:

  • embargo - the period of time during which an article will only be available on the publisher's website,
  • Self-Archiving -  the act of (the author's) depositing a free copy of an electronic document online in order to provide open access to it - of only certain versions of the article ex. preprint (i.e. a pre-review article) or postprint version (i.e. the final, reviewed version of the article, but without the editorial cover of the journal), while prohibiting the distribution of the publisher version, i.e. the version that can be found in the journal. Publishers often also determine the licence under which publications are made available.

The OA policies of individual journals can be checked on the Sherpa RoMEO service, which collects information on the OA policies of individual publishers. The database can be searched by publisher name, journal title or ISSN. Four colours are used to indicate publishers' policies towards preprints and postprints:

  • Green – can archive preprint and postprint or publisher’s version/pdf,
  • Blue – can archive postprint (i.e. final draft post-refereeing) publisher’s version/pdf,
  • Yellow - can archive preprint (i.e. pre-refeering),
  • White – archiving not formally supported.

Most journals/publishers usually set out the conditions under which their published material can be re-published on open access in Institutional repositories.  Authors can check the publisher's copyright and self-archiving policies using the Sherpa RoMEO or DOAJ (Directory of Open Access Journals) websites.


Gold Open Access

The publisher make all articles and related content available free of charge on the journal’s website immediately after publication. There are two variants:

Full Gold OA or Pure Gold OA - the publisher makes the article freely available upon publication. The cost of publication is covered by a one-off fee, an APCs (Article Processing Charges), paid by the author or institution. APCs vary from journal to journal, covering the entire cost of the publication process e.g. peer-reviewing, editing, publishing, maintaining and archiving, and allows immediate access to the full text versions of the research articles.
Hybrid Gold OA - authors publish in traditional subscription-based journals, but can choose gold access for their publications by paying the APC. Once the article is published, it is open to all readers.

Differences between Green OA and Gold OA


Diamond (Platinum) Open Access

Publication via diamond journals/platforms that do not charge author-facing publication fees - APCs (Article Processing Charges). Diamond open access journals are usually funded via library subsidy models, institutions or societies.

Action plan for Diamond OA


Black Open Access

A publication that is not openly licensed, or for which reuse rights have not been granted, which is shared online illegally. Black OA often involves ignoring copyrights and not paying the financial costs of processing an article. Black OA users use free access to digital versions of articles, often without the authors’ knowledge and consent.