The traditional model of academic publication is built upon subscriptions. These highly expensive subscriptions, most often paid through libraries or other cultural institutions, allow researchers access to journals and other materials. Yet these journals include articles typically protected by copyright laws that restrict their use and distribution.
Open Access, on the other hand, is the practice of making peer-reviewed scholarly research freely available online. Rather than publishing their research through traditional journals, scholars opt to publish their research within journals dedicated to Open Access materials. There are two versions of Open Access: Libre and Gratis.
Gratis Open Access allows scholars to access and read research without payment. Libre Open Access, on the other hand, is also gratis. Yet this version of Open Access comes with additional benefits, typically a Creative Commons license, allowing researchers to reuse and remix content.
In addition to these versions, Open Access includes two additional formats, based upon the route that research is made available online. Green Open Access, for example, includes research that a publisher makes available online freely. The research, however, must be placed within a subject or institutional repository. And the publisher may require the research go through a period of embargo, typically 6-24 months.
The other format, Gold Open Access, includes publishing research directly onto a publisher's platform. Research published in this manner is often available immediately and remains accessible permanently. However, publishers of this type of research typically include fees authors must pay for publication.