Galley proof A proof of text copy before being made into pages.

Gamma A measure of contrast in photographic images.

Gapless Plate or blanket cylinders without gaps.

Gathering In binding, the assembling of folded signatures in proper sequence.

GCR (Gray Component Replacement) A technique of replacing gray areas with black, in order to affect the progressively more saturated tones and produce a long, broad black.

Gear streaks In printing, parallel streaks appearing across the printed sheet at the same interval as gear teeth on the cylinder.

Generation Each succeeding stage in reproduction from the original. A copy of an original would be the second generation.

Giclée prints (pronounced 'jee-clay') French for "sprayed ink", these are prints made with inkjet technology. Fine art prints and posters for the most part. The main issue to consider is archival quality. Most of these inks are water-based and may fade over time. Some at least are pigment based and therefore more archival.

Gigabyte (GB) One billion bytes.

Glyph A single letter, symbol, or number from a font.

Grain The direction in which most fibers lie that corresponds with the direction in which the paper is made on a paper machine.

Grammage A term in the metric system for expressing the basis weight of paper. It is the weight in grams of a square meter of the paper expressed in g/m2.

Graphical User Interface See GUI.

Gray balance The dot values or densities of cyan, magenta, and yellow that produce a neutral gray.

Gray level The number of gray values that can be distinguished by a color separation filter - usually 28 or 256.

Gray scale A strip of standard gray tones (in analog or digital form), ranging from white to black, placed at the side of original copy during photography to measure tonal range and contrast (gamma) obtained.

Gripper edge The leading edge of paper as it passes through a printing press. Also, the front edge of a lithographic or wraparound plate secured to the front clamp of a plate cylinder.

Gripper margin Unprintable blank edge of paper on which grippers bear, usually about 1/2" or 1.5 centimeters.

Grippers In sheetfed printing presses, metal fingers that clamp on paper and control its flow as it passes through.

Groundwood pulp A mechanically prepared wood pulp used in the manufacture of newsprint and other publication grade papers.

GUI (Graphical User Interface) Pronounced "gooey," in digital imaging, a technical term for a system that lets users manipulate files by pointing to pictures (icons) with a mouse or other pointing device instead of having to type in key commands.

Gum arabic In offset lithography, used in platemaking and on press to protect the non-printing areas of plates.

Gumming In platemaking, the process of applying a thin coating of gum to the non-printing areas of a lithographic plate.

Gutter The blank space between page columns or the inner or outer margin space from printing area to left and right page edges. More space is usually required in the binding fold area.