Abstract: An offset rotary machine including a printing unit with two plate cylinders which are arranged at a predetermined distance from each other. The two plate cylinders are mounted so as to be engageable and disengageable alternatingly against a rubber blanket cylinder and an inking mechanism. A single inking roller is pressed against the engaged plate cylinder. Only a single dampening roller of the dampening mechanism is pressed against the inking roller. The alternating engagement of the two plate cylinders makes it possible to carry out a flying plate exchange while maintaining the ink/water balance and, consequently, preventing a misprint until the ink/water balance has been reached. Moreover, an additional printing unit, inking mechanism and dampening mechanism is not necessary for the flying plate exchange.

Abstract: Copy to be transferred to an intaglio form for printing is first photolithographically reproduced as a basic discontinuous-tone image which is then photoelectrically scanned and converted into a dot pattern by computerized engraving of an intaglio-printing surface. The engraving may be carried out mechanically or by inscribing the dot pattern on a film with the aid of a laser and then projecting it onto a pigment carrier to produce a latent image upon which a blurred halftone replica of the basic image is superimposed to extend the tonal range by selectively deepening the pits subsequently etched into the printing surface.