"An intaglio print is the mark left on a sheet of paper by metal plate
that has been carved and inked”
(JM Billard, « Paroles de graveurs », Dessain et Tolra)
Direct or Cold methods
Dry point scratches and lifts tiny metal chippings and the resultant burr of metal that is raised holds more ink that the incised line itself and gives a velvety stroke. The plate wears out rapidly because the burr soon breaks off during printing.
The burin digs deep and sharp lines.
Mezzotint necessitates the preparation of the metal plate : Using a serrated tool, the entire metal plate is rocked to produce a roughned surface. The marks left by the serrated tool leave burrs that absorbe the ink and yield a rich and velvety black. Then using scrapers and burnishers, the printmaker can bring out shadows, lights and half tones
Indirect or Hot methods
The etcher coats the plate with a varnish which he/she scratches using an etching needle or another metallic point. He/she then dips the plate in an acid solution (ferric chloride or nitric acid). The acid bites the metal where the varnish is scratched and incises a burrless line.
Aquatint is a work on surfaces. The acid bites filtered by powered rosin allows for a range of tones from the ligther to the darker and a range of finish front he rougher to the smoother.