The way that Open Access is provided depends on choices made by author(s) and the organisations that fund their research. There are two models for creating Open Access to published research. These are called the Gold Route and the Green Route.
The Gold route describes a situation where the author or a third party pays the publisher an article-processing charge [APC] to cover the cost of peer reviewing and publishing an article, which is then made available free of charge to everyone.
The Green route, also called self archiving, describes a situation where the publisher agrees to allow a version of the article (pre-print or post-print) to be made available on the author's web page or through the institutional repository of the place where they work. Typically this would be a university or research institution. The publisher still publishes the article in a paid for/subscription based journal to recover their cost. For more information on publishers policies towards the Green Route/self archiving visit the SHERPARoMEO website.