Gg

g
(1) symbol in metric system for gram; (2) abbreviation for gravitation constant.

gable roof lock
a type of display lock used in gable roof construction.

gal
abbreviation for gallon, US.

galley
a shallow metal tray used to hold type.

gallery camera
refer to process camera.

galley proof
a reader proof taken of type in a galley before it is formated into pages.

gallon, Imperial
a unit of volume in the British Imperial System used in liquid and dry measure equal to 4,546 liters, abbreviation Imp gal.

gallon, U.S.
a unit of volume or capacity in the US Customary System used in liquid measure eqal to 4 quarts or 3.785 liters, abbreviation gal.

galvanized
process of coating steel frames with rust resistant zinc.

galvano screen
specialized rotary screen used for long runs on a rotary screen printing press.

gamma
(1) a measure of contrast in photographic images; (2) mathmatical curve representing both contrast and brightness of an image.

gamma correction
a non-linear tonal correction, editing an image gamma curve.

gamma curve
the shape of a line connecting the input and output values responsible for generating an image.

gamut
greatest possible range.

gamut chart
a small text image for evaluating the reproducible colors in process color printing.

gamut color
the cleanest, most saturated color that can be reproduced by a set of process inks on a given substrate.

gamut compression
editing an image to reduce the color gamut so that the image can be displayed or output within the limits of a particular device.

gamut mapping
plotting the color of an image into the CIE color space.

ganging up (gang): the reproduction of a number of differnent jobs or multiples of a single job that print as a single impression.

garment discharging
a process that allows the printing of dyed-dark textiles with light colored designs, by using sulfoxylate reducing agents with special dyes; refer to discharge printing.

gas chromatography
an analytical instrumental method of determining the composition of volitale solvents and oils.

gas crazing
under certain drying conditions the wrinkling of a printed film produced with tung oil.

gas mixer
a control valve for mixing air and gas.

gate
orifice through which liquid resin enters the mold in plastic molding processes.

GATF
acronym for Graphic Arts Technical Foundation (US).

GATF star target
a quality control aid composed of a circular target approx. 17cm (5/8 in) with pie shaped wedges of lines that converge in the center. (It is printed with color bars on the edge of a press sheet to detect dot gain, slur, and double images).

Gaussian blur
an image softening effect utilizing a bell shaped Gaussian distribution curve.

gauge
(1) any of various instruments or tools for precise measuring; (2) to measure exactly; (3) a standard of measure, dimension, or capacity.

gauze
an European designation of a class of screen printing fabrics comprising both silk and synthetic fibers.

GB
acroynm for gigabyte.

Gb
acroynm for gigabit.

GCR
acroynm for gray component replacement.

Geflect stitch
refer to fiel stitch.

gel
(1) a state or condition where an ink or vehicle demonstrates a semi-solid or jelly-like consistency; can refer to deterioration to an unworkable condition; (2) partially cured plastisol ink that is dry to touch 79º-116ºC (175º-240ºF) but not completely cured 135º-171ºC (275º-340ºF).

gelatin
a glutinous protein type colloid used as coating for photographic film and screen emulsions.

gelatin emulsion type film
any photosensitive film, or one that can be rendered photosensitive that is compounded to be water-soluable on a colloid base.

gelatin stencil
a screen printing stencil made from gelatin, colloid emulsion or film.

gel point
the stage at which gelatin begins to form into a semi-solid consistency.

generation loss
the loss of quality that is unavoidable in any type of analog duplication, not present in digital duplication.

generator
any person or company that produces hazardous waste as defined by the U.S. Environmental Protection Agency (EPA).

generic
not identified by a specific trademark or tradename.

geometric distortion
image deformation in a uniform manner.

geometric printing
to the screen print fabricated objects other than flat sheets such as glassware, cylindrical, spherical, and other irregular shapes.

germicidal lamp
a low pressure mercury-vapor lamp operating between one and ten watts per linear inch, and used as a UV energy source in conjunction with those units utilizing an inert atmosphere.

ghosting
(1) an image of the printed design or copy that extends beyond the limits of the stencil, usually with less ink deposition than the intended print area, caused by the slight creeping of improperly stretched screen mesh; (2) wet-on-wet printing, resulting in offsetting of wet prints onto the back of the screen.

ghost image
(1) ink stains on screen mesh that were not removed during screen cleaning and reclaiming; (2) image that remains on a substrate after chemically removed or washed..

giclée (Fr. "a spraying of ink")
term for fine-art digitally produced prints.

GIF
acronym for Graphics Interchange Format; an eight bit (256 colors or shades of gray) or less computer file format used to post photographic images to bulletin boards.

giga
a prefix utilized in the metric system of measurement that denotes 10 to the ninth power (10⁹ ) or 1,000,000,000; symbol is G.

gigabyte (GB)
an electronic unit of measure equal to one thousand megabytes or one billion bytes.

giga ohms
measure of electrical resistance in a dielectric material.

GIGO
acroymn for garbabe in garbabe out.

Gilsonite®
trademark of a natural black bitumen sometimes used in the formulation of black printing ink.

glacial acetic acid
a chemical used in fixing baths and in stock hardener solution that is 99.8% pure.

glass
(1) refer to loupe; (2) an inorganic product of fusion that has couled to a rigid condition without crystallizing.

glass blowing
the forming or shaping of molten glass by air pressure.

glass ceramic
a material melted and formed as a glass, then crystallized by controllled heat treatment.

glass colors
colored glass flux or enamel used to decorate glass.

glass etch
any of several compounds that permit the frosting of glass by acid based screen printing directly on the ware.

glass transition temperature (Tg)
midpoint of the temperature range over which a material undergoes a phase change from brittle to rubbery or visa versa.

glassine
a class of smooth, lightweight, dense paper that is usually semi-transparent and coated on one or more faces with silicon or similar agent that inhibits adhesion to another surface; once used as a stencil material.

glaze
a vitrous mixture of complex borates and silicates, either colored or clear, that attaches itself firmly to the body of ceramic ware, imparting a gloss and smoothness to the surface.

glazed paper
paper with a high gloss or polish.

glitch
minor unexpected malfunction, mishap, or technical problem.

glitter
small bits of light reflecting decorative material added to a material or ink to achieve a sparkle appearance in the final product or print.

glory hole
an opening in a furnace for the purpose of reheating glass during hand fabrication.

gloss
the relative degree of shine or luster of a substrate or material, the higher the light reflectance from the surface, the more shiny the substrate.

gloss ink
an ink that dries with minimum penetration into the substrate surface and that yields a high shine or luster.

glossmeter
an instrument used to measure the specular reflectance of light from a surface of a material at a given angle.

glossy print
a photographic print that has a shining finish.

glost
glazed ceramic ware.

glost fire
to kiln fire bisque ware to which glaze has been applied.

glost kiln
kiln for firing glaze on ceramics.

glueability tester
instrument used to test the strength of a bond formed between an adhesive and a material, by mechanically separating them until the adhesive bond breaks, with measurement readings in pounds of glueability.

glue pot
a heated receptacle used to melt thermo material prior to use.

glue screen
a printing screen for the application of adhesives.

gluing machine
a mechanical device for applying adhesive to a substrate.

glycerin
an oderless, colorless liquid C₃H₅(OH)₃ of the alcohol class used as a solvent in the manufacture of alkyd resins and ester gum type inks.

glycol
alcohol containnig two hydroxyl (-OH) groups.

glycol ether
a chemical family of solvents, some of which have been used in screen printing ink formulations; includes 2-methoxyethanol, 2- ethoxyethanol, and their acetates that are now restricted in US due to toxicity.

gob
a glob of molten glass delivered to a mold for forming.

gold caratage
a measure of purity or fineness of gold. (24 karat represents pure gold).

gold ink
a metallic screen printing ink which has the appearance of metallic gold.

golden rod paper
a specially coated yellow or orange masking paper used to assemble and position negatives for exposure to press plates.

goniometer
an instrument used to measure contact angles of droplets placed on a substrate surface to indicate surface energies/wetting capabilities.

Gosudarstvenny J Komitet Standartov
standards organization in Russia.

gothic style letter
letter that is without serifs, small spurs, or extensions at the terminals such as a sans serif typeface.

gouache
a method of painting with opaque colors that have been ground in water and mingled with a preparation of gum.

gout
a clump of any foreign body trapped in a fabric during the weaving process.

gpd
abbreviation for grams per denier.

gr
abbreviation for grain.

gradation
gradual change of tones from one shade to another.

grade
to determine a type, category for various papers and cloth.(Paper grade categories are bond, uncoated book, coated book, text, cover, board, and specialty).

graduate
a container or vessel with markings on it for measuring volumes of liquids; also called beaker.

graft polymer
polymeric structure made by attaching monomers to long-chain molecules.

grain (gr)
(1) in paper, the direction in which the majority of the fibers lie; (2) smallest unit of weight used in American system of measuring based on the weight of a grain of wheat equal to 0.0648 gram; (3) fine textured appearance of a negative, print, or transparency resulting from the clumping of silver grains. (4) the smallest component of a photographic image. A single particle of silver or dye cloud. Collectively, the size of those particles.

graininess
an effect seen in the print as randomly occurring light and dark specks or grains, due to roughing of the edges of halftone dots, random specks of ink between dots, discontinuous ink films, or specular reflectance off inked fibers in the surface of the paper.

graining
the application and firing of one colored enamel over another to imitate a natural wood or marble finish.

grain long
the fiber direction in a sheet running parallel to the length of the sheet.

grain short
the fiber direction in a sheet running parallel to the short dimension or width.

grainy
small variations in the surface appearance of paper often caused by irregular distribution of color.

gram
unit of mass and weight in the metric system; the weight of one cubic centimeter of water at standard conditions; 28.35 grams equal one ounce; 453.6 grams equal one pound.

grammage
the weight of a square meter of paper, expressed in grams per meter squared (g/m²).

grand format/superwide
72" or greater width digital print machines or media. Their printing process was usually driven by air, but recent machines may piezo-print directly on a substrate.

granite wash
chemical or mechanical process that takes dye out of a garment to create a cracked look.

granularity
non-uniformity of photosensitive film emulsion, causing light scatter.

Graphic Arts Technical Foundation (GATF) (US)
a scientific, technical, and educational organization serving the graphic arts industry conducting research into graphic processes and applications, headquartered in Pennsylvania.

graphic overlay
the front panel containing the graphics in a membrane switch or other industrial application.

graphics interchange format (GIF)
a photograph or drawing stored in electronic form for viewing on a computer.

graphics tablet
a device that allows the user to plot position points on a tablet using a pen or stylus to input drawing coordinates.

graphite paper
a type of carbon placed beween acetate paper and porcelain.

gatefold
an oversized page where both sides fold into the gutter in overlapping layers.

generic fiber codes
acronyms developed by the International Standards Organisation for manufactured fiber.

golden ratio
a rule devised to give proportions of height to width when laying out text or images to produce the best optical appearance.

gravure printing
an intaglio printing process where the ink is carried in minute etched cells on the plate, the excess being removed from the surface by a doctor blade; also known as rotogravure printing.

gray balance
the combination of cyan, magenta, and yellow halftone dots that yield a neutral gray tint without hue for a specific press, substrate, and ink combination. (Gray balance elements are targets made up of overprints of cyan, magenta, and yellow halftone tints that are intended to appear as a neutral gray with no hue).

gray component replacement (GCR)
an electronic color scanning technique that determines the amount of black ink to be used to replace cyan, magenta, and yellow in areas where those three inks overlap; also refer to achromatic reproduction.

gray contact sheet
similar to the magenta contact screen except that the dots are gray in color and are sharper than the magenta screen.

grayed-down
a process of mixing black or the complement of the color to make the color gray; a neutral, muted variation of a pure color.

gray goods
fabric that has been removed from the loom, before any finishing or dyeing, also referred to as grey or greige goods.

gray levels
the number of steps available to reproduce a color in an imaging system. Typically, in an 8 bit system there are 256 gray levels per color.

gray scale
(1) a range of luminance values for evaluating shading through white to black; (2) a reflection or transmission scale of gray tones in steps from clear or white at one end to black at the other, with steps in-between showing evenly intensified series of gray tones. (It is attached to the original design or copy to determine accuracy of exposure and uniformity of color separations. Patches of yellow, cyan and magenta are included with the scale when photographing for color separations); also referred to as gray or step wedge.

gray scale continuous
continuous tone black and white image on film where the density gradually increases from zero.

grayness
attribute calculated from density readings that relate to the degree of three-color contamination in cyan, magenta, and yellow process color ink.

grease proof ink
ink or coating that is resistant to the action of fats, oils and greases.

green
one of the three additive primary colors of light.

green strength
(1) mechanical strength of an unfired ceramic greenware body; (2) the ability of an adhesive to hold two surfaces together when first contacted, but before the adhesive has developed its ultimate bonding properties (when full cured).

greenware
a formed ceramic article that has not been fired.

greige goods (gray goods)
knitted fabric in roll form before finishing.

grin through
loss of color saturation that occurs in knitted textiles when they are stretched and the undyed fiber shows through the printed design.

grinding
the process of pulverizing raw materials to a desired degree of particle size.

grindometer
instrument used to indicate the presence of coarse particles or agglomerates in an ink dispersion. (The fineness of grind is rated at the point on the scale where oversized particles first appear in concentration).

gripper edge
the leading edge of the substrate as it passes through the press.

gripper margin
an unprintable blank edge of a substrate on which the grippers bear usually 12.7 mm or _ inch or less.

grippers (gripping fingers)
mechanical fingers on a press that grasp or hold a substrate for positioning.

grit
the abrasive material on a grinding belt or wheel used for sharpening squeegee material.

grog
small particles of sand, bisque, or quartz that are added to a clay body to give it strength.

grommet
(1) a metal reinforcement, usually in the form of a round ring, mounted in the edge or corners of a printed banner for hanging; (2) a small rubber ring used to insulate a printing screen used in hot ink screen printing.

grommet and washer with teeth
a metal ring that is permanently attached by means of teeth in the washer.

grommeting
the process of applying metal reinforcements (grommets) into holes punched in edges or corners of a banner, display, or sign unit for the purpose of hanging.

ground glass
a sheet of glass that is translucent at the back of a camera that can be moved into the focal plane in place of the film holder and used to assist in focusing the image.

grounding
the creation of a connection capable of transferring a static or electrical charge to earth ground.

growth
(1) expansion of graphic out of register due to screen stretch; (2) expansion of material due to mechanical embossing.

gsm
an acronym for grams per meter, a unit of measurement for paper weight.

GUI (Graphical User Interface)
abbreviation for Graphical User Interface, a computer operating or control system that applies graphics for the operator to command the computer with a mouse or stylus.

guide pin
a pin that aligns closing mold halves.

guide edge
the side of a substrate that is at a right angle to the gripper edge.

guides, register
stops on the printing base against which edges of substrate are placed for printing to ensure that all substrates are being printed in identical areas or positions.

guillotine
a manual or electronic paper cutter with a straight blade that raises and lowers with the downward action being the cutting portion of the cycle.

guillotine cutting
the cutting of stacked sheet stock by straight line cutting with a suspended blade.

gum
a water soluable substance that hardens when exposed to air that is used as a resinous binder in ink and varnish formulations.

gum arabic
a water soluble organic gum of various species of acacia used as a binder in ceramic glazes and colors and other ink formulations.

gum tragacanth
(1) an orgain material of vegetable origin used as a binder in glazes and enamels; (2) an organic substance of vegetable origin used as a binder in water vehicle solutions, particularly those containing gelatins used in making photoscreen stencils; similar to gum arabic.

gusset
an added structure used to strengthen a formed plastic object.

gutter
(1) the taped interior edges of the screen parallel to the direction of the squeegee; (2) the white space along the inside margins of facing pages.

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