Green open access is when a version of an article, published as a subscription article, can be accessed for free.

Green open access means that you:

• Continue to publish in a subscription journal.
• Do not need to pay additional charges, as subscribers pay all the expenses needed to support the publication process.
• Share a link: Sharing a link to the article can be done immediately either via our Share Link service or with the article's permanent address (DOI).
• Self-archive: Authors can post a copy of their research for everyone to read for free. See our sharing policy for details. 
• Open archive: Everyone can read and download free archived material in 98 Elsevier journals after an embargo period. See a list of journals with open archives.

To enable open access for a subscription article, a time delay, known as an embargo period is needed. This begins from the publication date of the issue the article appears in. The embargo period is journal-specific and generally ranges from 12 - 24 months.

This is a way of publishing open access in a journal which ensures your article is immediately published open access. This type of open access is available in either:

• An open access journal, which doesn't have any subscribers.
• A journal which supports open access publishing, which is also known as a hybrid journal.

Gold open access means that:

• Your article will be peer-reviewed.
• Upon acceptance, a fee is payable by you or your research funder.
• You need to select a user license which will determine how readers can copy, distribute and use your research. This is normally one of the Creative Commons user licenses.
• Once published it is free permanently for everyone to access.