Universität Bonn

Open Access Service Center

Publication models

Gold, green, diamond — maybe you have often wondered what these all mean in the context of open access? Here is an initial overview.

One goal — many ways to get there

The idea behind open access, i.e. providing open access to research, is an aim that many people can quickly get behind. But there are many routes to this goal:
Authors can publish their findings in an open-access journal, an open-access book or a repository such as Zenodo, arXiv and bonndoc. Plus publications go through various stages and versions, such as preprints. The timing can vary too: for instance, a work may be published in an open-access format straight away or not until later.
Some simple terms have therefore been introduced for all these scenarios, most of them named after colors. The best-known are the gold and green models.

Infographic with start and finish and different paths (gold, hybrid, closed, green)
© CC BY 4.0, open-access.network, "Pathways of Open Access"

What types of open access are there?

Gold model/Gold open access

Schmuckbild goldene Fassade
© CC BY 2.0, "Polishing gold", Timmy_L

An article, a book or another type of research literature can be made freely accessible in full straight away. This method of publishing a work for the first time is known as “gold open access” and will often be done in a (quality-assured) periodical devoted exclusively to open-access content.

Putting an article in a gold open-access periodical may incur costs (also known as "article processing charges", or APCs), which are paid by the authors. However, we can help you with financing via our publication fund.

Green model/Green open access

Schmuckbild grüne Fassade
© CC BY-NC-ND 2.0, "Green and White", Rohit Mattoo

Often, an article, book or similar will be published for a fee first of all. Making a publication like this available again (at a later date) in an open-access format is known as green open access and allows you to make use of your right to publish work for a second time (§ 38 para. 4 of the Copyright Act (UrhG)). The green model is free of charge.

Repositories in an institution or department are the best form of infrastructure for this method. We can assist you with publication via green open access: your best option for this at the University of Bonn is to use bonndoc.

Diamond/platinum open access

Schmuckbild Fassade siber
© CC BY-NC 2.0, "2011-07-04b", Brenda Gottsabend

Diamond (or platinum) open access is a special form of the gold model. Works are published for the first time under an open-access model but without any costs to the authors, meaning that no APCs are incurred.
The financing is covered partly from institutional funds. The University of Bonn supports a large number of diamond OA initiatives, e.g. Open Library of Humanities, SciPost, SCOAP3, Open Book Publishers, Open Library Politikwissenschaft, KOALA.

We can help you go down this route yourself, e.g. when publishing your open-access journal.

Hybrid open access

Schmuckbild Fassade orange
© CC BY 2.0, "Gold wall", grassrootsgroundswell

Many publishers allows their authors to "unlock" individual articles from periodicals that continue to be subscribed to for a fee. These articles then become open access straight away. Such periodicals are hybrid in nature.
This form of open access is controversial, because it means that publishers benefit twice: as well as selling access to the periodical to research institutes and libraries, they also demand additional fees for releasing open-access articles. These fees are usually higher than the APCs in periodicals that publish only open-access content.

What else is available…

Not enough variety there for you? Then here is a brief introduction to some more terms that have become more or less established in the industry:

  • Bronze = articles and similar that are freely accessible via a website but that were not published under a free license. Whether this constitutes “genuine” open access is therefore a matter for debate.
  • Closed = articles and similar that are neither freely accessible nor open access. Closed access is thus the opposite of open access.
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