Q: What are the differences between open access and standard subscription-based publication?

Subscription-based journals typically require readers to pay for the content that they read. This has been the model followed traditionally in the academic publishing industry. Since individuals or institutions have to pay subscription charges, only those who have purchased a subscription to the journal/have purchased an article will have access to your paper. 

In the open access model, readers are not charged: they have free online access to the content. By allowing free access to the scientific community and to the public, the open access model definitely ensures a wider readership.

Another difference is that in the subscription model, copyrights for the published content are usually transferred to the journal, while with open access journals authors generally retain copyright. This means that for an article published in a subscrition-based journal, anybody who wishes to use any part of the paper will have to seek permission from the journal. OA journals, on the other hand, often use Creative Commons licenses (CC licenses), which make it easier for users to share, use, and build upon the original work. 

However, in the open access model, authors usually have to pay article-processing charges (APCs) once their paper has been accepted for publication.

You might also be interested in knowing about some other publication options offered by a journal.