Gamma

Gamma is the graphical area the abbreviation for gamma correction, a non-standardized method of measurement of contrast for scanners, monitors and photographic materials.

Background of gamma correction is that the human eye won’t perceive a uniform flow from white to black as mathematically linear. In the human perception of contrast is increasing less in the bright areas, while it increases steep in dark areas.

A gamma of 1.0 means no change in contrast. A gamma of 1.8 was historically recommended for Mac monitors, while Windows user has a gamma of 2.2 as the default recommendation. Today a gamma of 2.2 for Mac and Windows is recommended.

Higher gamma values ​​mean more contrast with darker midtones. Lower gamma values ​​represent lower contrast and brighter midtones. Gamma based on the white and black points of an image, which it also does not change.

For the color profile of Adobe RGB 1998 a gamma of 2.2 is defined, for ECI-RGB V2 an L * gamma.

Gamut

The gamut (also colour gamut) refers to the range of all colours in a colour space that can be recognised (camera, scanner) or reproduced (printer, monitor) by a device.
It is visualised in the form of a colour solid.

Gamut mapping

The conversion of colour values from one colour space (e.g. sRGB on the monitor) to another colour space (e.g. CMYK in print) so that the colour reproduction remains as consistent as possible.

GC1

GC1 refers to a coated primary fibre board (chromo board) in packaging printing.

Front surface layer = hf white
inlay = light
Back surface layer = hf white

hf white: wood-free white layer of bleached pulp with a maximum of 5% mechanical pulp

light = light layer of mechanical wood pulp or of a mixture of unbleached pulp and mechanical wood pulp

GC2

GC2 refers to a coated primary fibre board (chromo board).

Front surface layer = hf white
inlay = light
Back cover layer = light

hf white: wood-free white layer of bleached pulp with a maximum of 5% mechanical pulp

light = light layer of mechanical wood pulp or of a mixture of unbleached pulp and mechanical wood pulp

GCR

GD1

GD1 designates a coated secondary fibre board, insert and back grey
(chromo duplex board), top side wood-free white, with special volume (> 1.45 cm³/g).

Front side top layer = hf white
Inlay = grey
Back cover layer = grey

hf white: wood-free white layer of bleached pulp with a maximum of 5% mechanical pulp

grey = layer of recycled pulp (reused cellulose and groundwood fibres)

GD2

GD2 designates a coated secondary fibre board, insert and back grey
(chromo duplex board), top side wood-free white or slightly wood-containing white, with special volume (< 1.45 cm³/g, > 1.3 cm³/g).

Front top layer = hf or slightly hh white
Inlay = grey
Back cover layer = grey

hf white: wood-free white layer of bleached pulp with a maximum of 5% mechanical pulp

slightly hh white = slightly woody white layer of bleached pulp with a maximum of 30% mechanical pulp

grey = layer of recycled pulp (reused cellulose and groundwood fibres)

GD3

GD3 refers to a coated secondary fibre board, insert and back grey
(chromo duplex board), top side wood-free white or slightly wood-containing white, with special volume (< 1.3 cm³/g).

V = hf or slightly hh white
E = grey
R = grey

hf white: wood-free white layer of bleached pulp with a maximum of 5% mechanical pulp

slightly hh white = slightly woody white layer of bleached pulp with a maximum of 30% mechanical pulp

grey = layer of recycled pulp (reused cellulose and groundwood fibres)

GGZ

GGZ designates a cast-coated, fully bleached cellulose board in packaging printing.

Front surface layer = hf white
Inlay = hf white
Back surface layer = hf white

hf white: wood-free white layer of bleached pulp with a maximum of 5% mechanical pulp

GMG

GMG ColorServer is a company based in Tübingen, which has made a name with the development of color management software. For over 25 years GMG has been developing anything from printer drivers to complex Proof software.

With the proofing software GMG ColorProof GMG is with EFI / Fiery market leader in the graphic arts industry.

GOE

2007 PANTONE introduced the GOE color system with more than 2,000 colors, which was originally intended to replace the Pantone Matching System PMS. It was discontinued in February 2014 by Pantone and no longer exists in the market.

The advantages of Pantone GOE were obvious:

• With 2056 colors, it included nearly twice as much color as the Pantone Matching System with only 1,114 colors
• The colors could be made of only 10 basic colors
• The layer thickness of GOE was uniformly 1.3 gr / sqm and was so for printing more manageable than the sometimes very different layer thicknesses of the PMS
• A GOE color was mixed from a maximum of two basic colors and Pantone or PMS Black Clear. The formulations were uniform and clear.
• The color arrangement in the subjects was logically divided chromatically:
  • The first number was for the color family
  • the second number was for the subjects page within the family
  • the third number stood for the position on the fan page: 1 has always been the highest and brightest color, 7 the lowest and darkest color

Despite a lot of effort, Pantone GOE found little spread. While in 2008 GOE was integrated into all main software products such as Quark Xpress or the Adobe range, commercial printing companies usually denied the use of Pantone GOE. They simply didn’t understand the need for two different PANTONE systems with twice the costs for ink storage etc.

Pantone responded by extending the PMS with over 600 new colors to its current 1755 colors (03/2014). Pantone GOE has been discontinued in 2014, which hardly anybody noticed as GOE never was able to capture a significant market share.

Gradient

A colour that usually goes from saturated to less saturated over an area.
The gradient can also run from one colour to another, or several colours.

Gravure Printing

Gravure printing is one of the oldest printing processes that is still used today.

A distinction is made between sheet-fed gravure printing, for smaller print runs, and rotogravure printing, for larger print runs. The latter is also the most common process.

In gravure printing, the print image is engraved into the printing cylinder (or printing plate). It is then dipped into the ink and the excess ink is scraped off, leaving only the ink in the depressions (cells). Finally, this ink is transferred to the printing substrate using high pressure and the absorbency of the paper.
With less absorbent materials such as metal or plastic, this is achieved through electrostatic charge.

In addition to the high print quality, rich colours and an even ink application, gravure printing offers the advantage of regulating the amount of ink applied due to cells of varying depth. This way, halftones can actually be represented – something that offset printing can only simulate.

Gravure printing is mostly used for magazines and catalogues, plastic and metal foils, stamps, securities or even banknotes.
Gravure printing can also be used for artistic purposes, with the preference for hand-engraving.

Grey balance

Grey balance is the ratio of the primary colours (process colours) CMY (cyan, magenta, yellow) in four-colour printing, through which an optically neutral grey is achieved.

When RGB image data is separated, it is transferred to the CMYK colour space. The grey balance must be adjusted so that achromatic RGB values are also achromatic in print (grey balance correction).

GT

GT refers to a coated secondary fibre board.

Front top layer = hf white or light hh white
Inlay = grey
Back cover layer = light

hf white: wood-free white layer of bleached pulp with a maximum of 5% mechanical pulp

light = light layer of mechanical wood pulp or of a mixture of unbleached pulp and mechanical wood pulp

grey = layer of recycled pulp (reused cellulose and groundwood fibres)

GTI

The GTI GmbH is beside Just Normlicht a renowned manufacturer of standard light tubes and standardized light consoles and colour cabins. GTI offers numerous systems for colour assessment, but is- other than Just – opposed the use of LED, and therefore offers only special neon-based solutions. LEDs in the standard light industry are according to  GTI economically and qualitatively no real alternative to the renown and tested tubes.

Weblink: http://www.gtigmbh.de

GTIN

The Global Trade Identification Number is synonymous with 8- and 13-digit bar code.

The EAN or better: GTIN numbers contain the issuing country and a reference to the manufacturer as well as a serial product number and a check digit. The numbers are assigned worldwide by GS1.

The Proof GmbH is a member of GS1.

An article with tips for creating GTIN numbers for graphic designers can be found here. (German)

GZ

GZ refers to a coated, bleached pulp board in packaging printing.

Front surface layer = hf white
Inlay = hf white
Back surface layer = hf white

hf white: wood-free white layer of bleached pulp with a maximum of 5% mechanical pulp