Here is a quick and simple guide to the “rainbow” of open access terms.
Bronze
Freely accessible journal articles on publishers’ servers, but without clear details on reuse
Examples
- Archives of subscription journals
Limitations
Without clear licences, article reuse is highly limited
Gold
First publication as an article in Open Access journals. Publication costs are covered by authors, usually in the form of APCs.
Examples
- PLOS ONE
- Frontiers Journals
Limitations
Inequitable APC costs and the propagation of a highly damaging business model
Hybrid
Subscription-based journals that offer authors the option of paying a fee (APC) to make their individual articles freely available online under an open access license.
Examples
- There’s a long list here
Limitations
Institutions are often charged for APCs and subscriptions, resulting in them paying twice
Diamond
A publication is free of charge both for readers and for authors.
Examples
- There’s a long list here
Limitations
Publication costs still exist and sustainability is currently an unsolved issue
Green
Secondary publication of publications from access-restricted journals or books on institutional or subject-specific repositories.
Examples
- Preprint servers
- Author websites
Limitations
Publications may only be freely available after an embargo period
Black
Illegally obtaining closed access articles
Examples
- Scihub
Limitations
Primarily legal and ethical issues. It may also be difficult to source every article
Rippling Ideas 