I’ve already recommended MOMA’s YouTube Channel for those who are interested in learning about Modern Art, but they also have some excellent technique videos as well. In particular, I find their series Pressure and Ink to provide great information about printmaking. Specifically, they have detailed demonstrations (with solid explanations) of relief printing, intaglio printing, and lithography. If you are interested in trying out printmaking (or if you have no idea what it is), I strongly suggest you take a look at Pressure and Ink.
Videos: MOMA’s Pressure and Ink
Humanities Scholars 