(autotypical color mixture, halftone color synthesis in French: synthèse autotypique) optical effect combination of additive and physical color mixtures of transparent to opaque inks when they are printed adjacently or partly overlapping, in the form of periodical (AM) or non-periodical (FM) screens. The additive mixing effect (preferably adjacent printing) diminishes as the absorptive mixing effect (preferably superimposed printing) increases. The basic colors in the standard process are the additive secondary colors Cyan], Magenta] and Yellow…

automatic/closed-loop color density control (In French régulation de l’encrage) automatic control of color density in printing presses, integrating color measurement or color density measurement in a closed signal flow circuit, e.g. KBA QualiTronic ColorControl.

ASTM (American Society for Testing Materials) US institution, which among other things develops test methods for inks, e.g. D387:2008 (standard test for the color and strength of pigments) or WK20008 (block resistance).

approved press sheet, OK sheet (In French BAT, bon à rouler, bonne feuille, épreuve acceptée) sheet printed at the end of the setup of the production printing press, approved as a visual and metrological production print reference. assessment appréciation the Delta E detected is assigned to categories by means of predefined tolerance intervals, e.g. “unnoticeable”, “small” or “large”.

appraisement, appraisal (In French évaluation) technical or visual comparison between reference and sample; the result is a color difference Delta E.

ANSI US standards institute; developed the IT8 targets in color management, among other things.

anilox screen (In French trame aniloxe) dot structure on inking roller in flexo printing and waterless offset printing with short inking units (KBA technology).

anilox roller (In French rouleau/cylindre anilox) designation for ink and varnish feed rollers whose origin is in former flexo printing with “aniline dyes”; the screen-type engraved ceramic surface (“screen roller”) has also proved to be advantageous in water-less offset short inking units (KBA Gravuflow/Newsflow, KBAMetroPrint), since the ink key control of inking is implemented through the viscosity-dependent ink transfer quantity with the help of a tempering device.

alpha channel (In French canal alpha) in image editing programs, besides the color channel, additional channels (1 or more) in which transparency information is defined with 8 bits per pixel (RGBA); the values range from 0 (transparent) to 1 (opaque).

ageing (In French vieillissement) 1) Property of light sources to lose brightness with increasing service life, with its spectrum also shifting; bulbs and fluorescent lamps are more severely affected than LEDs, which is why the latter are being used more and more as steady standard light sources (see Just). 2) Long term process of chemical decomposition of layers of ink through external influences, e.g. solar radiation, rainwater, frost.