Ways to Open Access

Ways to Open Access

Frequent questions


Ways to Open Access

Green route: This involves publishing in open-access repositories, which are an alternative for publication and scientific communication based on international open-access initiatives. This is the route promoted as a priority among the research community. Institutional, thematic, or general repositories mostly deposit the final version of published documents so that they can be made openly accessible, sometimes after an embargo period. They include journal articles, papers, book chapters, or any other form of scientific publication in digital format, available online and, in many cases, in full text.

Diamond route: the publisher or journal offers immediate open access publication completely free of charge, i.e. without charging authors for publication or readers for reading. Both publication and access to the published materials are free of charge, as these publications are usually funded by academic institutions, governments or scientific societies.

Golden path: this consists of publishing in open access journals after payment of APC (article processing charges), covered by the author or the institution to which he/she belongs. This supports free access to the content by the public.

Hybrid model: in the same journal, alongside paid-for articles, there are also open access articles for which authors pay in exchange for their article being in open access. This option is known as open choice.

Open access publishing platforms are another way to disseminate your research results in open access. 

Among them, Open Research Europe (ORE) has been launched by the European Union for the publication of research resulting from Horizon 2020, Horizon Europe, and/or Euratom funding in all thematic areas (Natural Sciences, Engineering and Technology, Medical Sciences, Agricultural Sciences, Social Sciences, and Humanities). It works in two ways: as a repository and as an academic journal so that the research community can share its results and knowledge. It does not charge any APC fee to those who publish the results of research funded by the European Union and is committed to an open peer review model: once the preprint is published, the peer review is done in an open and transparent way. In addition, there is no limit to publication; everything that exceeds a minimum level of quality is published. If you want to know more about open access publications, we recommend you to consult the following directories:

What are repositories?

Their main objective is to collect, archive, preserve and disseminate in open access the scientific and scholarly output of an institution. They facilitate access and increase the visibility and dissemination of the deposited works.

Depending on the type of repository, the deposited objects vary. They can range from doctoral theses, journal articles, conference papers, teaching materials to raw primary research data or any other form of research results, scientific publication, academic or institutional output in digital format.

These digital files usually contain the "preprints" or "postprints" versions of documents prior to publication:

  • Pre-prints”: a version of a document that corresponds to the original document, before it has been peer-reviewed and before it is accepted for publication.
  • Postprints”: final version of a peer-reviewed paper incorporating suggested changes or corrections, which will be the final version accepted by the editor.

Infographic: benefits of publishing in CRUE repositories

What type of repositories exist?

  • Institutional repositories: these are linked to specific institutions and store, preserve and disseminate scientific, academic or institutional output.
  • Thematic or disciplinary repositories: these are repositories that bring together resources and documents related to a specific discipline or subject area.
    • Arxiv: for mathematics, physics, computer science, biology, finance and statistics
    • BioRxiv: specialised in life sciences
    • CiteSeerX: for computer and information science
    • Pubmed Central: specialising in life sciences and biomedical specialties
    • RePEc: for the field of economics
    • TechRxiv: for computer sciences 
  • Data repositories: these repositories are for storing, sharing and protecting research data.
    • European Union open data portal a single access entry point to a large variety of data generated by educational institutions and other EU organisations. This repository enables individuals to use, reuse, link to and redistribute data without charge for any commercial or non-commercial purpose.
    • Zenodo: developed under protection of the OpenAIRE project and CERN, this repository compiles and shares multi-disciplinary research data from any scientific community, researcher or research institution.

How to find repositories

  • International ranking of repositories
  • Directories of repositories: these provide organised access to repositories.
    • OpenDoar: Directory of Open Access Repositories
    • Roar: Registry of Open Access Repositories
  • Search for repositories
  • Repository collectors: these enable you to search through and access materials and resources from all of the repositories covered, simultaneously and using a single interface.
    • OAIster: union catalogue providing millions of records of open access resources. This catalogue was created by compiling material from open access collections from all over the world. OAlster currently has over 50 million records representing digital resources from over 2,000 collaborators.
    • OpenAire: Open Access Infrastructure for Research in Europe. An online repository infrastructure which aims to support the application of open access to science in Europe.
    • Recolecta: lists and provides access to scientific documents provided in open access format in Spanish institutional repositories.
    • Hispana: collection and directory of digital resources from archives, libraries and Spanish museums managed by the Ministry of Culture.

What is the embargo period to publish in a repository?

It is the period that a publisher exclusively reserves to provide public access to a work or document after its publication.

The length of embargo periods vary depending on the journal or publisher, but usually range from 6 to 24 months. During the embargo period, which begins with the date of formal publication, the document cannot be made available in full text through a repository.

Once this period has elapsed, the repository can publish the version of the document agreed with the publisher, usually the postprint, in open access.

Tools for finding the embargo periods of publishing houses and journals

To include documents that have already been published with a publisher in an open-access repository, it is essential to be familiar with the editorial policies and copyright rights related to the contents they publish. 

For this purpose, international and national portals have been established:


Sherpa-Romeo: international website that compiles the author rights policies and self-archiving policies the main publishers and journals around the world. It includes information on the version or versions of the document that may be published on an open access basis and on applicable embargo periods.


Dulcinea: Spanish website that compiles the publishing policies of Spanish journals regarding access to their archives, exploitation rights, and publishing licenses. It includes information on the version or versions of the document that may be published on an open access basis and on applicable embargo periods.

Other Open Access resources

  • Hedatuz: digital library of Basque culture and science
  • Dialnet: joint project with a key focus on increasing the visibility of Hispanic scientific literature. It consists of journal articles, books, articles from joint volumes, conference proceedings, doctoral theses and so on. It also provides a referencing alert system and a repository which provides access to Hispanic scientific literature in complete text format.
  • Digital.CSIC: open-access scientific repository of the Higher Council for Scientific Research (CSIC)
  • DOAJ: Directory of Open Access Journals
  • DOAB: Directory of Open Access Books
  • REDALYC:initiative driven by the Autonomous University of the State of Mexico, providing open access to scientific production in Latin American journals
  • Europeana: European digital library, providing open access to more than 45,000,000 materials from more than 2,300 European institutions.