 Open access. What's with all the colors? If you're talking about open access, the two colors you're most likely to hear are green and gold. These are used to describe two different paths to open access, ways of achieving the end goal of open sharing. Green open access refers to copies of publications that are made available to the public in a location other than their original venue of publication. Usually this involves self-archiving, like posting on a website or in an institutional or subject repository. Gold open access refers to publications that are made available to the world in their original place of publication, that is, their published open access to begin with. There are some ups and downs to both of these options. Green open access can be a little bit slow because it usually requires action from individual authors, but there are opportunities for green open access to happen on a broader scale. One of the advantages of green open access is that it's a path to open access that's very much in the hands of authors and researchers themselves. The only change from traditional publishing is that the authors have to retain a few rights. Publishers don't have to do anything. One of the perceived downsides to gold open access is the idea that it's costly for authors, but that's actually a misconception. Some publications where all of the works are open access from the first original date of publication don't charge any author fees at all. A lot of the confusion over the costliness of gold open access arises from a separate issue, and that's the hybrid model of providing access to articles. Hybrid refers to actually a hybrid between closed and open access. An otherwise closed publication makes individual articles available openly, but only if the author pays an extra fee. This does actually fall under the definition of gold open access because the original publication is openly available, but it is not the only kind of gold open access. It may be helpful to remember that there is both paid gold open access and free gold open access, and that the gold part isn't about money, it's about having the gold standard, the original print formatted version, of the article available to the public. Just to confuse everything, Sherpa Romeo, which is a tool that helps track publisher archiving policies, i.e. a tool for helping achieve green open access, uses similar colors to categorize a publisher's policies, but these colors are less likely to come up in general open access discussions. There's more complexity to both green and gold open access, and many people have strongly held opinions about which is best or which is better. In the end, any of the colors do provide public benefits, more access to more published research literature for more people in more parts of the world.