Etching

The Intaglio Printing Process

Aquatint example
  • Etching is a process where the design has been produced through the biting action of acid.
  • This technique is over 500 years old.
  • The word “etching” is used to describe both the process and the resulting print on paper.

Etching Tools and Plates

etching plate & tools etching plates & tools

 

Coating the Plate

Metal plate is first coated with an acid-resistant material called a “ground.”

brushing ground on plate painting on asphaltum

 

Drawing on Ground

Exposing the Metal

  • The artist draws an image on the plate using a metal tool with a pointed tip.
  • The drawn lines expose the metal plate.
drawing on the ground Exposing the plate

 

Etching or Biting the Plate

  • The plate placed in an acid bath.
  • Exposed parts of the metal are eaten away by the acid.
  • Grooves are produced in the plate that will hold ink.
plate in acid bath etching bath with feather
biting the plate plate in acid bath A feather is often used to brush away bubbles that form so the bite of the acid will be clean.

 

Acid Bottles
  • One recipe for nitric acid solution: 3 parts water to 1 part concentrated nitric acid.
  • Nitric Acid and zinc in a 10:1 concentration will etch a densely crosshatched area pretty well in 5 to 60 minutes. An aqua- tint will be etched in 5 to 60 seconds.
nitric acid molecule

Copper Plate

  • Ferric Chloride (iron perchloride, FeCl3) and Copper in a 42 baume solution will etch a densely crosshatched area pretty well in one to 3 hours. An aquatint can be etched in 5 to 60 minutes.
  • Dutch Mordant (potassium chlorate, KClO3 and hydrochloric acid) is also used to etch copper.
  • Potassium chlorate should be handled with care. It reacts vigorously and in some cases spontaneously ignites or explodes when mixed with many combustible materials. It is used in some recipes for gunpowder, generally replacing the less powerful ingredient potassium nitrate. 

Copper Vs. Zinc

So ....... why use copper and ferric chloride when zinc and nitric acid seem to work so much faster?
There are two answers:

  • Copper is a more consistent metal that etches “cleaner” than zinc.
  • Ferric chloride is a relatively harmless etching agent whereas nitric acid is quite dangerous to handle.

 

Etched Copper Plate
etched copper plate

 

Close-up of Etched Plates
  • Aquatints give areas of shading.
  • There are many pits in the metal to hold the ink.
copper plate close up
magnified etched copper plate

 

etched plate coated with ground

Etched Plate with Ground

A clear ground of wax painted over an already etched plate for further work.

 

Inking & Printing

  • Ink is wiped into those grooves or pits the acid has etched onto the plate.
  • The plate is run through a printing press and the image is transferred onto damp, high-quality, acid-free, linen-based paper.
inking a plate

Inking the Plate

  • The plate is cleaned to remove the ground.
  • Ink is applied to the entire plate and rubbed off the flat surface, leaving ink in the grooves.
inking zinc plate

 

Plate on Press Bed
plate on press bed

 

Covered with Felt Blanket
covered with a felt blanket

 

Felt Etching Blankets
felt printmaking blankets

 

Pulling the Print pulling a print pulling the print

 

Canceled Etching Plate
canceled etching plate

 

Rembrandt Etching

Self-Portrait, 1620

rembrandt etching self portrait

 

Nautilus