"Open Access stands for unrestricted access and unrestricted reuse. With Open Access, researchers can read and build on the findings of others without restriction. Much scientific and medical research is paid for with public funds. Open Access allows taxpayers to see the results of their investment. Open Access means that teachers and their students have access to the latest research findings throughout the world." - Public Library of Science, https://www.plos.org/open-access.
Green Open Access: self-archiving your accepted manuscript in an open and free to access institutional repository (like Fisher Digital Publications). Publishers or journals that allow for immediate deposit of scholarship in an institutional or subject repository are Green Open Access. An embargo period usually applies.
Gold Open Access: publishing your "version of record" or official work on the publisher or journal's website. Usually fees (frequently called Article Processing Fees/Charges) are paid by the author or institution to make work freely available.
This video was created by Natalie Ross and Anna Standish. https://creativecommons.org/licenses/by/4.0/
SPARC (Scholarly Publishing and Academic Resources Coalition) Director of Programs and Engagement Nick Shockey and Professor Jonathan A. Eisen talk about the impact of Open Access. https://creativecommons.org/licenses/by/4.0/.