Glossary

The PRINTING United Alliance Glossary serves as an excellent industry terminology resource. It is the language by which we all communicate. Without it, universal understanding would be impossible.

To keep our constituents well informed about changes to the increasingly complex industry terminology, PRINTING United Alliance has developed this glossary of terms. Definitions are for general reference only. Usage may vary between companies, individuals, or national and country customs. The information presented is as accurate as the authors and editors can ascertain and PRINTING United Alliance assumes no responsibility for the use of information presented herein.
  • Coated paper
    Paper with a very thin clay coating on one or both sides of the sheet (C1S/C2S) with a finish ranging from eggshell to glossy.
  • Coated screen
    A printing screen with direct emulsion applied to the mesh prior to exposing.
  • Coating
    (1) An unbroken clear film applied to a substrate in layers to protect and seal it or to make it glossy; (2) A screen printed material, pigmented or clear; applied to a substrate and forming a continuous film.
  • Coating mottle
    A small variation in gloss that can be detected on a coated, calendered sheet by viewing the sheet at an angle to check for specular reflection from the surface.
  • Coating pigments
    Mineral materials used for coating paper stock such as clay, (the most common), talc, calcium carbonate, titanium dioxide, and zinc oxide.
  • Coating screen
    A printing screen designed to print a solid layer of clear varnish or ink over a large predetermined area, usually used for applying color to backgrounds of displays or similar uses.
  • Coating weight
    The mass of an applied coating per square unit of surface area sometimes referred to as mass weight.
  • Cobalt drier
    A liquid material containing chemically combined cobalt, used to accelerate oxidation and polymerization of an ink film, promotes drying.
  • Cobb test
    A method used to measure the water absorption of seized paper by determining the weight of water absorbed through one surface under pressure.
  • Cobwebbing (angel hair)
    Fine filaments or strings resembling cobwebs that project at random from the edge of the ink or coating on the substrate.
  • Cockle
    (1) An irregular lump in a fabric thread; (2) A desirable paper finish in cotton fiber sheets produced by air drying paper with controlled tension.
  • Cockling
    An undesirable effect in paper identified by the uneven, rippled appearance of the paper surface caused by improper drying.
  • Coefficient of thermal expansion - linear
    (1) The fractional part of its length that a material elongates when raised one degree Celsius in temperature; (2) Fractional change in length or volume of a material divided by the change in temperature.
  • Cohesion
    (1) Mutual attraction of elements that bind the particles of an ink or varnish film together; (2) The ability of an adhesive to resist splitting; (3) The forces holding a single substance together.
  • Cohesive failure
    The rupture of an adhesive bond such that the separation appears to be within the adhesive.
  • Cohesive strength (cohesion) (internal bond)
    The internal strength of an ink or adhesive, due to the mutual Attraction force between like molecules.
  • Cold color
    (1) An organic enamel for glass decorating that is baked at a low temperature, usually under 260 degrees C (500 degrees F); (2) A bluish or greenish hue.
  • Cold cracking
    Deterioration of a plastic from cold temperatures causing stiffness and even brittleness, breaking or shattering under stress as temperature is lowered.
  • Cold curing
    The process of curing at normal atmospheric temperature.
  • Cold end
    Packing end of a lehr or intake end of conveyor dryer where heat is used to aid drying.
  • Cold flow (ooze)
    The viscous flow of a pressure sensitive adhesive under pressure or other stress, at room temperature; also refer to creep.
  • Cold peel
    Process where the release paper of a plastisol transfer is not removed until the heat of application has dissipated.
  • Cold setting ink
    Solid ink that is melted and applied as a liquid through a heated printing screen, solidifying again on contact with the substrate that is not heated.
  • Cold temperature adhesive
    An adhesive that will induce a bond to a cold substrate.
  • Cold weather adhesive
    An adhesive formulated to be usable at 0 degrees C (32 degrees F) or other specified low temperature.