Intaglio is a generic term used to describe the process of engraving a groove into a sheet of metal. Ink is pressed into that etched line, the surface area polished clean of ink and pressure applied to transfer the ink to a sheet of damp paper.  The various techniques are etching, engraving, mezzotint, aquatint, dry point and soft ground.  The prints are most commonly referred to as etchings.

The depth of the etched line will determine the darkness of the line as a deeper etch will hold more ink. A soft delicate line or texture is a shallow indentation of the plate.