"The Gates of Central Park"
Top: Etching - Printed image
Bottom: Inked Copper Plate

How a Line Etching is Created

Image above shows the line etching on top and the copper plate it was pulled from on the bottom.

1.    Coating the Plate with Ground
A clean copper plate is coated with acid resistant ground (similar to a thin coat of wax).

2.    Drawing the Image
The image is drawn onto the plate, through the ground and in reverse with an etching needle.  

3.    Biting the Plate in an Acid Bath
The plate is immersed in an acid bath.  The acid “bites” into the metal where the ground was scratched away creating a depression/incised line in the copper.  The longer the plate is in the acid, the deeper the bite, thus the darker the printed line.  I work from the darkest areas to lightest.  The darkest areas are drawn first and are immersed in the acid bath, then I draw the next darkest areas and once again immerse the plate in the acid bath, then the next darkest, etc.  The areas that are exposed to the acid bath the longest create the largest and deepest lines in the copper, which hold more ink than the shallower lines.

4.    Inking the Plate
When complete the ground is removed with a solvent and ink is spread onto the plate.  The excess ink is removed by buffing the plate with a tarlatan (a stiff cheese cloth) and then to clean areas further, with the heel of the hand.  Ink remains in the incised lines.

5.    Printing the Image
Once the plate in inked, it is placed on the press bed and covered with a damp piece of printing paper.  As it is cranked through the press the plate passes between two rollers.  The pressure of the rollers forces the damp paper into the recessed lines where it picks up the ink.  
The process can take from a week for a 2” x 2” print up to 4 – 5 months for a 12” x 12” plate.