This document discusses and compares green open access (self-archiving published works in repositories) and gold open access (publishing in open access journals that are freely available online). It provides definitions of these terms from various organizations. It also outlines recent open access policies from funding bodies and governments in the UK, Europe, US, and Australia that generally support both green and gold open access. Empirical evidence is presented that open access articles tend to receive more downloads and citations than articles hidden behind paywalls. Instructions are given for authors to self-archive works in La Trobe University's research repository to provide green open access.