Intaglio

Engraving:
V-shaped trenches are cut in the surface of a highly polished metal plate by a tool called a graver or burin, which is pushed along the surface. The graver is a bar of steel with a V-shaped cross section and a sharpened end, which acts like a scoop or gouge, and cuts out a shaving from the metal surface along which it travels, like a plough cutting a furrow; the strength of the line may be increased by cutting deeper. The tool has a handle, usually made of wood, though frequently it is merely an old cork, which rests against the ball of the hand while the metal shaft is held in the fingers. No matter how sharp the graver is, it always leaves a minute burr along either side of the trench that it cuts in the metal surface. Early engravers let this burr wear away in the course of printing off the plate, but later artisans scraped the burr away before they began printing. Engraving is a slow and painstaking technique producing controlled, formal results.

Drypoint
Lines are scratched into the soft metal plate using a tool, usually a small bar of steel with a sharp round point, which is held like a pencil. Cutting into the plate throws up, on each side of the cut, ridges of displaced metal, which are called burr. The amount of burr depends upon how hard the point is pressed into the surface and the angle at which it enters. In the printing of the plate, these ridges will also take some ink and print a kind of inky glow around the line, but the burr wears away very rapidly in the course of printing.

Etching
Lines are bitten into the polished metal plate through the use of acid. First, the plate is covered with a thin, acid-impervious coating called a ground, made primarily of wax, which is smoked to a uniform black. Lines are drawn through the ground with a stylus or etching needle, visibly baring the shiny metal of the plate. Then acid is applied, which eats into the exposed metal areas. In theory, the etcher presses just hard enough on the point to scratch through the ground but not to dig into the plate. The acid bites, or dissolves away, the bright metal exposed in these lines, but does not go through the ground. The longer the plate is exposed to the acid, the deeper the bite, thus producing a stronger line. Varying depths are achieved by covering some lines with acid-impervious varnish (stop-out) and biting others a second or third time. The ground is then removed and the plate inked and wiped. The appearance of etchings is usually free and spontaneous, but the technique has occasionally been used to produce results almost as formal as engraving.

Note: These three processes are frequently used in conjunction. An etched plate can be touched up or finished in either or both engraving and drypoint. Very fine engraving can be touched up in drypoint and the burr then removed from the drypoint touches. It is very difficult to distinguish between light engraved lines and drypoint lines from which the burr has been removed.

Aquatint
A technique that utilizes acid-biting of tone rather than lines. A ground is used that is not completely impervious to acid, and a pebbly or granular texture (broad or fine) is produced on the metal plate. Stop-out and second and third bitings are used to produce variations of darkness.

Mezzotint
Mezzotint is the only intaglio technique that proceeds from dark to light rather than light to dark. The metal plate is totally abraded with an in instrument called a rocker. Were it inked and printed at this point, it would produce an even, rich black. The design, in areas of tone rather than lines, is produced entirely by smoothing areas of the plate with a scraper or a burnishing tool, the more scraping and burnishing done, the lighter the area.

Printing Intaglio Plates
Printing intaglio plates is basically the same no matter what particular processes have been used on them. Stiff, tacky ink is spread over the warm plate and worked down into its lines. The plate is then wiped with rags and finally with the palm of the hand to remove the ink from the metal surface but not from the lines or scratches in it. This done, the inked plate is laid face up upon the bed, or plank of a roller or etching press. Damp paper is laid on the plate and over the paper are placed felts or pieces of blanket. The handles of the press are then pulled and the bed with its burden is run between two heavy rollers. The pressure of the rollers on the blankets crushes the damp soft paper into the lines in the plate so that it takes up the ink from them.

In all intaglio prints except mezzotint, the design is produced from the ink in lines or areas below the surface of the plate. The smooth surface is wiped clean of ink before printing, though some ink may be purposely left behind for tonal effects. Then considerable pressure is used in the press to force the ink out of these lines and areas, and, to an extent, to force the paper into them, so the final image will appear to be slightly raised above the surface of the uninked paper.

 

Works Cited

Goodfriend, C & J. Print-Making Techniques: An Abbreviated and Simplified Guide. NY, NY.
Ivins, William M., How Prints Look. Beacon Press: Beacon Hill, Boston, MA. 1943.

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