Glossary

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GAP

The space between two (2) objects.

GAPPING

Openings between layers within a roll of self wound laminating tape.

GAMMA

GASSA

GAUGE

A unit of measure. Usually the thickness or diameter and generally expressed by a number. Refer NS.

GAUGE BANDS

Areas where material or liner is thicker, forming a hard ridge as layer after layer builds up in the same spot.

GEAR CHART

A handy reference compilation of the various printing lengths or repeats obtainable within the different gearing systems of rotary presses. Referred to as ‘teeth per inch = TPI’ or ‘teeth per centimetre = TPM’.

GEAR MARKS

A defect in flexographic printing. Usually appears as uniformly spaced, lateral variations in tone exactly corresponding to the distance between gear teeth.

GEAR SIDE - See DRIVING SIDE

GEAR STREAKS

In printing, parallel streaks appearing across the printed web at the same interval as the gear teeth on a cylinder. Same as gear marks.

GEL

A state or condition in which an ink, varnish or coating has a jelly-like consistency.

GELLING

The thickening of an ink or other liquid, which cannot be reversed by stirring.

GHOSTING

Very faint reproduction of printed design without actual ink transfer. Shadows or indistinct images appearing in solids or reverses typically caused by poor ink distribution and/or poor ink formulation.

GLASSINE

A supercalendered, smooth, dense, transparent or translucent paper manufactured primarily from chemical wood pulps which have been beaten to secure a high degree of hydration of the stock. Commonly used as backing paper (liner). Refer NS & LM Specification Sheet.

GLOSS

Characteristic of the surface which causes it to reflect light at a given angle. Refer NS & LM Specification Sheet.

GLUE - See ADHESIVE

GRAB - Also called TACK (Initial)

Ability of an adhesive to quickly adhere to a surface with a minimum of pressure (usually touched to the surface with its own weight). Also called instant adhesion or initial tack. Refer NS & LM Specification Sheet.

GRAIN

In paper making, the direction in which most fibres lie corresponding with the alignment of the fibres in the direction of the paper travel through the paper making machine.

GRAIN DIRECTION

In roll or fanfolded labels, the grain direction runs along the web, parallel to the sides. The opposite of ‘cross direction’.

GRAM

Unit of weight in the metric system; the weight of one (1) cubic centimetre of water at standard conditions. A litre of water weighs 1 kilogram, 28.35 grams = 1 ounce, 453.6 grams = 1 pound.

GRAVURE PRINTING

A printing process employing minute engraved wells (cells). Generally, deeply etched wells carry more ink than a raised surface (letterpress and flexographic), hence print darker values. Shallow wells print lighter values. A doctor blade wipes excess ink from the cylindrical printing surface. Rotogravure employs etched cylinders and web-fed stock.

GUARD BARS

The bars which are at both ends and center of a UPC and EAN symbol. They provide reference points for scanning.

GUILLOTINE

An instrument for trimming sheets of paper (with a downward cutting action). Guillotines are usually ‘stand alone’ pieces of equipment, but on some label presses, they are built into the main machine.

GUM - See ADHESIVE.

Referring to a broad class of synthetic and natural adhesive materials which exhibit good tack characteristics. Refer NS & LM Specification Sheet.