the intaglio : a centuries-old technique
The intaglio refers to a method of engraving on a metal plate. The hollow, often microscopic, are created on the plate. Intaglio opposes the “line-engraving” and the “saving-engraving”. In the first, the ink settles in the hollow, while in the second, the ink is applied to the surface.
The plate is covered with ink and this several times, with a helping hand to the line-egraver size-doucier. Then ink in excess is wiped with a rag and then with the flat of the hand. So grooves are filled with ink.
The metal plate printing is done on a press in intaglio. The paper is placed and pressed against the plate, by the press or a roll. Then the paper is removed, this ink in the hollow was transferred on paper.
the intaglio : definition and types of processes
Initially, the intaglio refers to the burin engraving, used notably by the goldsmiths. It then saw designate all engraving on metal intaglio processes. Due to the predominance of the copper in the plates, the word of chalcography (engraving on copper) is obscured.
Intaglio processes are also on other metals, such as zinc or brass. Techniques are generally divided into two categories:
- The “direct engraving” when the artist serious directly the metal plate. This is the case of the burin, line-engraving drypoint, etching engraving, stipple, Mezzotint.
- The indirect, when engraving size results from the bite of a chemical solution. For example the etching, engraving to the lavis, aquatint, soft varnish, pencil way.
The great accuracy of drawing, permitted by the intaglio has notably intended in the manufacture of banknotes and of postage stamps.
A banknote printing, the writer realizes drawing to reproduce upside down on a soft metal punch. After any touch-ups, the recorder will harden the punch. For steel, the punch undergoes a process of dipping (temperature rise then brutal cooling). The print is then made with an intaglio press.
For postage stamps, the stamp is reproduced to compose a matrix, to print a full sheet of stamps. After that the achieved punches have hardened, they reproduce dozens of punches that will be held in plates or cylinders. Once the latter has been made, printing starts. Metal punches wear out gradually.
Sometimes that wear of a Board of punches is not noticed and that defects will print on the final Board. Philatelists spoke of “varieties” and “types” to designate other slightly different stamps.