Gold vs Green vs Diamond Open Access: Which One Is Right for Your Paper?
"Open access" sounds like one single thing, but it actually describes several different funding models with real practical differences for authors — mainly, who pays, and when the paper actually becomes freely readable.
Why "Open Access" Alone Doesn't Tell You Enough
Two journals can both call themselves "open access" while operating completely differently — one charging authors a publication fee for immediate free access, another charging readers a subscription while allowing a delayed, author-archived copy elsewhere. Knowing which model you're dealing with tells you what to actually expect, and who's expected to pay for what.
Gold Open Access
The final, published version is immediately and freely available on the journal's own website. Typically funded by an Article Processing Charge (APC) paid by the author (or their institution/funder) rather than the reader. This is the most straightforward model: pay once, publish, and it's free for anyone to read forever.
Green Open Access
The journal itself may be subscription-based, but the author is permitted to self-archive a version of the paper — often the peer-reviewed accepted manuscript before final journal formatting — in an institutional repository or a platform like arXiv. Access to the free version may also be subject to an embargo period before it's allowed to go public.
Diamond Open Access
No fee to either the author or the reader. The journal is instead funded by an institution, government grant, scholarly society, or similar third-party support. This removes the author-side cost entirely, but it depends on funding that isn't available to every journal, every field, or every publisher — which is exactly why it remains less common than Gold OA for independently-run journals.
A Note on Hybrid Journals
Some subscription journals offer a "hybrid" option: the journal is subscription-based by default, but an individual author can pay an APC to make just their specific article openly accessible within an otherwise closed journal. This is functionally Gold OA applied selectively, article by article, rather than journal-wide.
Side-by-Side Comparison
| Model | Author Pays? | Reader Pays? | Immediate Access? |
|---|---|---|---|
| Gold | Yes (APC) | No | Yes |
| Green | No (usually) | Possibly, for the journal version | Often delayed by embargo for the free version |
| Diamond | No | No | Yes |
| Hybrid | Yes, per-article | Only for non-OA articles in the same journal | Yes, for the paid article |