CASRAI Dictionary

Tag: diamond open access

  • What Is Open Access? Routes, Licences and Policy Explained

    Open access is the practice of making peer-reviewed research literature freely available online, free of most copyright and licensing restrictions, so that anyone may read, download and reuse it. The concept was formally defined by the 2002 Budapest Open Access Initiative and reinforced by the 2003 Berlin Declaration, both of which describe free availability on the public internet alongside the right to reuse work with proper attribution.

    Understanding open access means understanding two things at once: the routes by which an article becomes openly available, and the licences that govern what readers may do with it. The two are related but distinct, and policy frameworks such as Plan S operate across both.

    How open access is defined

    The Budapest Open Access Initiative (BOAI) defined open access as literature that is freely available to read, with users permitted to copy, distribute and reuse it for any lawful purpose, subject only to attribution. The Berlin Declaration added the requirement that a complete version be deposited in at least one suitable repository. Together these established that open access is about more than zero price; it is about removing permission barriers too. This distinction is often summarised as gratis open access (free to read) versus libre open access (free to read and reuse).

    The main routes to open access

    Several established routes describe how a work reaches readers. Each carries different cost and reuse implications for authors and institutions.

    Route Where it is hosted Who typically pays Key characteristic
    Gold The publisher’s journal, immediately open Author or funder, often via an APC Final version of record is open at publication
    Green A repository (institutional or subject) No author fee A version is self-archived, sometimes after an embargo
    Diamond A community or scholar-led journal Neither author nor reader No charges to publish or to read
    Hybrid A subscription journal with an open option Author or funder, via an APC Individual articles are opened within a paywalled title

    The gold, green and diamond routes are explored in depth in our companion guide on green, gold and diamond open access routes explained. Hybrid publishing remains controversial because the same article can be paid for twice, through subscriptions and an article processing charge, an outcome critics call double dipping.

    Creative Commons licences and reuse

    Licensing determines what readers can lawfully do. Most open-access publishing uses Creative Commons (CC) licences, which let authors retain copyright while granting standardised permissions.

    • CC BY permits any reuse, including commercial, with attribution. It is the licence most aligned with the BOAI definition of full reuse.
    • CC BY-SA adds a share-alike condition, so derivatives must carry the same licence.
    • CC BY-NC excludes commercial reuse.
    • CC BY-ND permits redistribution but not derivatives.

    The Directory of Open Access Journals (DOAJ) indexes journals that meet recognised quality and licensing standards, and is widely used to identify reputable fully open-access titles. Choosing a licence is a key decision for any author preparing a submission; our guidance for authors covers how licence choice interacts with funder mandates.

    Embargoes and the green route

    Under the green route, publishers may impose an embargo period during which the self-archived version cannot be made public, typically applied to subscription titles to protect their commercial model. The version permitted is often the accepted manuscript rather than the final published version of record. Repositories listed by institutions and disciplines, such as preprint servers, support this route at no cost to authors.

    Plan S and cOAlition S

    Plan S is a policy initiative launched by a group of research funders organised as cOAlition S. Its central principle is that research resulting from funded grants must be published in compliant open-access venues or made openly available without embargo, with funders willing to cover reasonable costs. Plan S has accelerated interest in fee-free models, and recent developments are tracked in our coverage of Plan S and diamond open access in 2026. The policy sits within the broader knowledge equity agenda, which treats open access as a route to fairer participation in scholarship.

    APCs versus no-fee models

    Article processing charges (APCs) fund gold and hybrid publishing by shifting costs from readers to authors or their funders. While this removes the paywall, it can create a barrier for researchers without grant support, particularly in lower-income settings. Diamond open access avoids charges entirely by funding publication through institutions, libraries or scholarly societies, and is increasingly seen as the most equitable model. The trade-off is sustainability, since diamond journals depend on continuing non-commercial support.

    Frequently asked questions

    Is open access the same as free to read?

    Not exactly. Free to read corresponds to gratis open access. The fuller libre form, defined by the Budapest and Berlin declarations, also grants reuse rights, usually through a Creative Commons licence such as CC BY.

    What is the difference between gold and diamond open access?

    Both make the final version openly available at publication. Gold open access is often funded by an article processing charge, whereas diamond open access charges neither authors nor readers, relying instead on institutional or society support.

    Does Plan S require a specific licence?

    Plan S strongly favours licences that permit full reuse, with CC BY as the default expectation, so that funded research can be read and built upon without permission barriers.

    Where can I check whether a journal is genuinely open access?

    The Directory of Open Access Journals (DOAJ) is a widely used index of vetted fully open-access journals. You can also consult our standards dictionary for definitions of the key terms used across open-access policy.

  • Diamond open access and bibliodiversity: equity in the scholarly record

    Open access was supposed to be an equity project. Removing the paywall meant a researcher in a poorly resourced institution could read the same literature as one at a wealthy university. In large part that promise has been kept on the reading side. But the dominant route to it — author-pays open access — has quietly reintroduced inequity on the writing side, and the response to that problem is reshaping how we think about an equitable scholarly record. This article sets out the landscape, drawing on the knowledge-equity domain.

    The flavours of open access, and where the barrier moved

    The vocabulary of open-access routes is worth getting straight, because the equity argument turns on the differences between them.

    • Gold open access makes the article openly available immediately at the publisher, typically funded by an Article Processing Charge (APC) — a fee charged to authors.
    • Green open access achieves openness through author self-archiving of a manuscript in a repository, at no charge to the author.
    • Diamond open access is open to both authors and readers at no charge: no APC, no subscription. The costs are met by institutions, libraries, funders, or scholarly societies rather than by the individual author.

    The shift to gold open access solved the reader’s paywall but erected an author’s paywall in its place. An APC of several thousand pounds is trivial for a well-funded lab and prohibitive for an unfunded researcher, a Global South institution, or a humanities scholar without grant money for publication. APC waivers exist for authors meeting low-income-country or financial-need criteria, but a waiver is a discretionary favour, not a structural fix, and the burden of asking falls on exactly the researchers least able to bear it.

    Diamond open access as the structural answer

    Diamond open access is the model that removes the barrier rather than waiving it. Because neither author nor reader pays, the equity question does not arise at the point of publication at all. The model is not new or marginal — a large share of the world’s open-access journals already operate this way, particularly those run by universities, societies, and national infrastructures — but it has historically been invisible in policy discussions dominated by the APC economy.

    That is changing. Plan S, the initiative of the funder coalition cOAlition S, mandates full and immediate open access to funded research and has increasingly recognised diamond routes as fully compliant, not merely tolerated. The significance is that the most influential open-access policy lever now actively legitimises the model that does not charge authors, which begins to correct an incentive structure that had quietly privileged the APC route.

    Bibliodiversity: more than one way to publish

    Diamond open access is one expression of a larger principle: bibliodiversity, the diversity of publication venues, languages, business models, and ownership in scholarly communication. The argument for bibliodiversity is that a scholarly record dominated by a handful of large commercial publishers, a single business model, and one working language is fragile and exclusionary. Resilience and equity both come from plurality.

    Concretely, bibliodiversity means valuing multilingual publishing rather than treating English as the only legitimate language of record; it means recognising community-owned and society-run venues alongside commercial ones; and it means counting infrastructures built outside the global North as first-class scholarly infrastructure rather than as regional curiosities. A bibliodiverse record is one where the language of original publication is metadata to be preserved, not a deficiency to be corrected.

    The Global South was here first

    It is a common misconception that diamond open access is a recent northern invention. The most mature diamond infrastructures in the world are in Latin America. SciELO — Scientific Electronic Library Online — has operated a region-wide, no-fee open-access infrastructure since the late 1990s, and AmeliCA articulates an explicitly community-controlled, non-commercial vision of open access for Latin America and the Global South. AfricArXiv extends preprint infrastructure to African scholarship. These are not pilots; they are working demonstrations that a scholarly record can be open to authors and readers alike, at scale, without an APC economy.

    The lesson the Global South infrastructures offer is not that the North should build its own diamond journals from scratch, but that an equitable scholarly record already exists in places that northern policy has been slow to recognise — and that recognition, not reinvention, is the first task.

    Why this is a metadata problem too

    Equity is not only an economic question; it is also an infrastructural one, and infrastructure is where CASRAI’s mission touches it. A diamond journal, a multilingual output, or a Global South venue is disadvantaged whenever the metadata systems that index, count, and reward scholarship cannot represent it cleanly. If a discovery system assumes one language, if an assessment exercise counts only venues in a northern-centric index, if an output’s persistent identifier ecosystem is thin, the bibliodiverse record is penalised by the plumbing even when policy intends to support it.

    Representing the full diversity of venues, models, and languages in shared, structured metadata — with DOAJ as the curated registry of open-access journals, persistent identifiers for outputs in every language, and vocabulary that does not assume the APC model is the default — is part of what makes equity operational rather than aspirational. This connects to responsible assessment: an evaluation system that values contribution and context over venue prestige is one that bibliodiversity can survive.

    Where shared vocabulary fits

    The terms in this domain carry real consequences, and they are easy to muddle: gold is not diamond, a waiver is not the same as no-fee, bibliodiversity is more than “some journals are open”. A shared, federated vocabulary that defines these precisely — pointing to cOAlition S for Plan S compliance, to DOAJ and OASPA for the publishing landscape, and to the Global South infrastructures for the diamond model in practice — is what lets equity goals be stated and measured without ambiguity. Supplying that definitional layer is the role the CASRAI dictionary is designed to play.

    What to do now

    For funders: recognise diamond routes as fully compliant and fund the infrastructures, not just the APCs. For institutions and libraries: invest in community-owned and Global South infrastructure as scholarly infrastructure. For standards work: ensure metadata and vocabulary represent multilingual, no-fee, and community-owned venues as first-class, so the plumbing does not penalise the bibliodiverse record.

    Related reading

  • Green, gold and diamond open access: routes explained

    “Is it open access?” sounds like a yes-or-no question, but open access is not one thing. It is a set of distinct routes — conventionally labelled by colour — that differ in who pays, what licence applies, where the work lives, and, crucially, who is included or excluded by the economics. Those differences are not technicalities: they determine whether open access widens participation in scholarship or quietly reproduces existing inequities. That is why the routes belong in the knowledge-equity domain. For the plain-language starting point, see What is open access?

    First, what open access actually means

    True open access is more than “free to read”. It means a work is freely available online and carries reuse rights, normally via a Creative Commons licence — most often CC BY. The reuse rights are the part people forget: a paywalled article temporarily made free, or a PDF posted with all rights reserved, is free-to-read but not openly licensed, and so not fully open access. Holding that distinction in mind is what makes the colour scheme legible, because the colours differ precisely on the licence-and-venue axis.

    The two foundational routes

    Green open access — self-archiving

    Green open access is achieved by the author depositing a version of the manuscript in a repository — an institutional repository or a subject repository — making it freely accessible independently of the publisher’s paywall. Typically the deposited version is the accepted manuscript (the peer-reviewed, pre-typeset version), and access is sometimes subject to a publisher embargo before it can be made public. Green’s great virtue is that it costs the author nothing and works alongside any journal: the article can appear in a subscription journal while a green copy sits openly in a repository. Its limitation is that the openly available version may not be the formatted version of record, and embargoes delay access.

    Gold open access — open at the publisher

    Gold open access means the version of record is made openly available immediately at the publisher, under an open licence, on the journal’s own site. The question gold raises is who pays for it. In many gold journals the cost is recovered through an Article Processing Charge (APC) — a fee, often substantial, charged to the author or their funder. This is where the equity problem bites: an APC-funded gold model can simply move the barrier from the reader to the author, excluding researchers without grants or institutional funds, and bearing hardest on those in lower-income settings. APC waivers exist to mitigate this, but they are a patch on a model whose default is pay-to-publish.

    Diamond: open with no charge to anyone

    Diamond (or platinum) open access is the model that breaks the pay-to-publish bind: the version of record is openly available immediately, under an open licence, with no charge to authors or readers. Costs are met by the community — typically through institutional, library, scholarly-society, or public funding of the publishing infrastructure itself, rather than per-article fees. Diamond is the model most aligned with knowledge equity, because it removes the barrier at both ends: nobody pays to read, and nobody pays to publish. Much of it operates outside the large commercial publishers, and a substantial share of the world’s diamond journals are run by scholarly communities and supported by regional infrastructures — the Latin American platforms SciELO, Redalyc, Latindex, and the AmeliCA initiative being prominent examples of community-owned, fee-free publishing at scale. Diamond’s challenge is sustainability: it depends on continued collective funding rather than a per-article revenue stream.

    The other colours, briefly

    • Bronze — free to read on the publisher’s site but without an open licence. The publisher can withdraw access at any time, and reuse rights are absent. Bronze is free-to-read, not genuinely open.
    • Hybrid — a subscription journal that offers individual articles as gold (usually for an APC) while the rest of the journal stays behind a paywall. Hybrid is widely criticised for “double dipping”, where institutions pay both subscriptions and APCs.
    • Black — articles obtained through unauthorised channels. This is not a publishing model and not a route an author chooses; it is mentioned only because the term circulates.

    How Plan S reshaped the landscape

    The policy backdrop to all of this is Plan S, the initiative led by the funder coalition cOAlition S, which requires that research it funds be made openly available immediately, with no embargo, under an open licence (CC BY by default). Plan S deliberately accepts multiple compliant routes — gold in a fully open-access journal, green via immediate repository deposit under a rights-retention strategy, or publication in a diamond venue — while explicitly disfavouring hybrid as a long-term destination. Its mechanism for the transition was the transformative agreement, a deal between institutions and publishers (often called read-and-publish) intended to convert subscription spend into open-access publishing and shift journals toward full openness over a defined period. Whether transformative agreements are a bridge to a fully open future or a way of entrenching incumbent publishers’ revenues is one of the live debates in the field.

    Choosing a route

    1. Check your funder’s requirements first. If you are bound by Plan S or a similar policy, the compliant routes — immediate gold, compliant green, or diamond — are defined for you, and an embargoed green copy may not satisfy them.
    2. Prefer routes that do not price out colleagues. Where a strong diamond venue exists for your field, it is the most equitable choice. Where gold is the route, check for fee waivers.
    3. Always secure an open licence, not just free-to-read. A CC BY (or funder-mandated) licence is what makes the work genuinely open and reusable.
    4. Use green to complement, not as an afterthought. Even when you publish gold or diamond, depositing in your institutional repository improves discoverability and preservation.

    Where shared vocabulary fits

    “Open access”, “gold”, “green”, “diamond”, “APC”, and “transformative agreement” are used inconsistently across funders, publishers, and institutions, which makes a single open-access policy hard to apply across systems. A shared, federated vocabulary that defines these routes precisely — pointing back to cOAlition S for Plan S and to the recognised open-access definitions — is what lets a policy written for one context be understood in another. Supplying that definitional layer is the role the CASRAI dictionary is designed to play; the relevant terms sit in the knowledge-equity domain.

    Related reading