The open access (OA) movement is a recent transformation of traditional scholarly publishing seeking to eliminate or reduce the price and copyright barriers that deny access to information. There are two main models of OA publishing

• GOLD - Akin to traditional publishing whereby authors submit a work to be peer reviewed and is published at no cost for others to read.  Costs to fund the publication process may be assessed to the author through article processing charges (APCs), although many publishers charge no fee.

• GREEN - Applies to PubMed Central (PMC) and institutional repositories, like the NYU Faculty Digital Archive whereby authors may elect to have their published work deposited to be later accessed by the public at no cost.

...however, many traditional subscription-based journals have taken a "hybrid" approach - giving authors the option to make their article Open Access (terms & conditions may apply - see the journal's author or submission guidelines for details). 

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Publishing open access has several benefits, including:

Publishing open access is not without its drawbacks. Article processing charges (APCs), or fees paid by authors in order to make an article available under the open access model, are often quite expensive. The library provides author fee discounts for selected publishers to help with this.

Some bad actors take advantage of this publishing model. Predatory journals and predatory publishers are designed to look like legitimate journals, but fail to offer the rigorous peer review and editing offered by legitimate scholarly publishing operations.

Red flags include:

It is important for authors to evaluate the quality of journals before submitting manuscripts. Even journals that do not explicitly engage in predatory practices may still publish poor quality studies.