M

machine direction

The direction the paper web moved through the paper-making machine. The paper's grain direction is the same as the machine direction. See also: grain direction.

magenta

One of the four process colors, CMYK, with M standing for magenta. Magenta is a predominately red color with some blue. Magenta, together with cyan and yellow, is also one of the three subtractive primary colors. See also: process colors, subtractive primaries.

magnifier

An optical device used to observe very small details. Used for quality control. See also: linen tester; loupe.

mean line

See x-line.

mechanical

See paste-up.

mesh marks

A pattern of crosshatching visible in the dried ink of a screen printed piece. The condition may be caused by high viscosity ink that does not spread out properly or by the ink being pulled away as the screen is lifted off the printed surface.

middletones

See: midtone.

midtone

Those tones falling between halftone shadows and halftone highlights. Other Term: middletones. See also: quartertone.

mortise

See kerning.

multicolor press

Two or more self contained single color printing presses that are joined sequentially to produce multiple colors on a sheet of paper in a single pass.

Mylar

A registered tradename of Du Pont's clear polyester film. This durable film is used for stripping and outputting architectural and CAD drawings.