Basic principles of Open Access

Essentially, there are two different approaches to Open Access. The so-called golden way is defined as measures that focus on Open Access primary publications, currently mainly Open Access journals. The so-called green way, on the other hand, means the additional provision of publications that have appeared in (closed-access) journals.

• „Golden Way": First publication of the scientific text in an Open Access medium that follows the conditions of Open Access. The Directory of Open Access Journals (DOAJ) lists around 14,000 journals and over 4,500,000 articles by Beginning of 2020. In geoinformatics, for example, this includes the journal Remote Sensing – An Open Access Journal by MDPI, with an impact factor of more than 3.
• „Green way": Additional provision (parallel publication or self-archiving) of publications that have appeared in (closed access) journals. This can be done on private homepages, institute homepages or document servers. The authors store a copy of their article or monograph, which they have submitted to the publisher, publicly accessible on one of the mentioned infrastructure elements. This mainly includes repositories or document servers. A distinction is made between institutional repositories (many universities and research institutions) and disciplinary repositories (subject-specific). An overview can be found in the Directory of Open Access Repositories - OpenDOAR.
• „Hybrid way": The payment of a fee (Article Processing Charge (APC)) to optionally exempt an article already published by a publisher in a closed access journal is controversial.

In addition, there is a greater grey area and diversity, which do not always make the interpretation of Open Access very easy.