Specular reflection of light. Occurs when specular reflection exceeds the diffuse reflection from various viewing angles. Can be measured with various geometries of illumination. For most printing papers, gloss is measured at an angle of 75 to 85 degrees to a plane normal to the surface.
Glossy Paper
Paper that has undergone advanced calendering on a supercalender. Steam and pressure are applied to burnish the paper and improve uniform reflection of light.
Grain
The direction that fibres in a sheet run. Indicative of the direction in which paper is made on a paper machine.
Grain Long
The grain of paper is parallel to the long dimension of a sheet of paper. E.g. 45 x 64cm., long grain, indicates that the grain is traveling in the 64cm direction.
Grain Short
The grain of the paper is parallel to the short dimension of a sheet of paper, or at right angles to the long dimension. E.g. 64 x 45cm, short grain, indicates that the grain is travelling in the 45cm direction.
Grammage
The term used to denote the weight of paper or board; the measurement used is the weight of a single sheet of one square metre, expressed as gramme per square metre (gsm). Grammes per square metre (GSM) · The gramme weight of one square metre of a particular type of paper; a good comparative measure because it does not vary with sheet size.
Gravure
An intaglio or recessed printing process. The recessed areas are like wells that form the image as paper passes through.
Green Bible
Robert Horne Group’s technical information, environmental information and technical capability guide sheets, collectively referred to as the Green Bible. Contains information for all paper and board stock items.
Green Claims Code
A Government-backed initiative designed to ensure that environmental claims about products and services are clear, accurate, truthful and able to be substantiated. See: www.defra.gov.uk/environment
Greenhouse Effect
The effect of gases such as carbon dioxide, methane and nitrogen oxides which allow solar radiation to reach the Earth but prevent it from escaping, which causes warming of the atmosphere.
Greenwash
Term sometimes applied to unfounded, misleading or inflated claims about environmental credentials.
Groundwood Pulp
A mechanically prepared wood pulp used in the manufacturing of newsprint and publication papers. See Thermo-Mechanical Pulp.
