Also called Article Processing Fees (APFs).
Not all Open Access journals charge these fees. Many high quality Open Access journals are funded through endowments, donations, or dues from members of professional and scholarly associations instead.
Author fees are called Submission Fees if they are charged before peer review, or Publication Fees if they are charged after peer review and once the article is accepted.
Since Open Access journals don't charge readers or libraries, most of them instead charge the authors who publish (or in some cases submit articles to be published) in them. These are distinguished from vanity publishers, who also charge author fees, but do not have quality control or selection criteria. Open Access Journals are refereed and held to the same standards as conventional scholarly journals.
Many conventional journals that are willing to give authors publication contracts that allow self-archiving (depositing the article in a repository - Green Road Open Access) also charge a comparable fee for that.
Authors who publish in journals that charge author fees should expect to pay between $200 and $5000.
Look at the journal's About section, FAQ, and Author Guidelines to find out what the author fees are, and whether they are charged for submitting the article whether or not it is published, or only if the article is accepted to be published.
Be sure to inquire about the journal's discounts and waivers of the author fee! The most common reason for a discount or waiver is financial need. You will most likely have to fill out an application.
Because the economic burden of publishing falls to the author, it is important to recognize that this can affect authors' publication decisions. Many factors go into deciding where to submit a paper:
While Open Access has many advantages for the author, the reader and the scholarly community, we must recommend that authors make their decision based on the interests of scholarship at large, rather than economic factors like author fees (which are extremely common in Open Access journals) or whether a local library has access to the journal (which it always will if it is an Open Access journal!)
But because author fees exist, in order to have the freedom to make a decision based on academic interests, you need to take possible author fees into account well before it comes time to submit your paper. Decide where you will submit early, find out the author fees and make a plan to cover those costs. Unless your institution covers author fees for you, write the cost into your research grant if at all possible.
Author fees create an inequity on the global scale and a problematic gap in the web of scholarly communication. This is because scholars from developing countries often can't afford to pay them, and therefore their works do not get published. Or if they do get published, they are published in journals that are local and small enough that researchers from the Global North do not have access to them.
In the interests of scholars being free to submit their papers to the most suitable journals, author fees must be covered by some source other than the author.
The two available sources are research grants and the author's institution.
The case for the author's institution covering the author fees is not all that radical.
Colleges currently pay for their faculty and students to read the scholarly literature through library budgets. Libraries subscribe to conventional journals, which operate on the reader-pays model. The subscription fees for these conventional journals are increasing faster than the rate of inflation. Colleges can contribute to the development of an alternative and more economically sustainable model by paying for their faculty and students to read scholarly literature through funding their own authors' contribution to the scholarly literature.
Furthermore, colleges should consider a policy of paying author fees for their faculty because research grants are drawn from limited pools of money and some disciplines are less well-funded than others. Requiring authors to fund their author fees through research grants will further widen the gap between the well-funded disciplines and the neglected ones.
Colleges uphold the values of academic freedom, which includes not only what scholars say, but the context in which they say it. In order for the scholars employed by a college to have academic freedom, their decisions of where to publish should not be constrained by either the economic pressure of author fees.
The downside is that authors at less prosperous institutions may experience more of a disadvantage in trying to publish in expensive Open Access journals, and those institutions may lose ambitious and talented faculty to institutions who can afford to pay for their scholarly output. However since scholars can move institutions more readily than they can move disciplines, and since the scant resources in some areas of study by no means indicate that those areas of study can be safely dispensed with, it is probably better to pay for author fees systematically out of institutional budgets rather than haphazardly through research grants.