halftone cell

Definition: Unit used by a halftoning printing or reproduction system to simulate gray-scale or continuous tone reproduction. * In mass-production printing e.g. off-set lithography, the half-tone cell is defined by the screen frequency, measured as lpi (lines per inch): continuous tone is simulated by using dots of different sizes within the half-tone cell. * With desk-top printers e.g. laser and ink-jet printers, the half-tone cell comprises groups of individual laser or ink-jet dots e.g. 16 dots arranged as a square of 4 by 4 may represent one cell, giving 5 gray-scale steps thus: no dot in the cell is white, 16 dots is black; with greys lying in between. * Halftone cells are always much larger than a printer's stated dpi (dots per inch) rating and are the useful practical measure of a printer's spatial resolution.

Related Terms: dpi, lpi

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