Printing terms demystified

D-I
(Continued from previous issue)
Deckle Edge
Edge of paper left ragged as it comes from the papermaking machine instead of being cleanly cut. Also called Feather Edge.

Diffusion Transfer
Chemical process of reproducing line copy and making halftone positives ready for paste-up.

Digital Dot
Dot created by a computer and printed out by a laser printer or imagesetter. Digital dots are uniform in size, as compared to halftone dots that vary in size.

Dot Gain
When halftone dots print larger on paper than they are on films or plates, reducing detail and lowering contrast. Also called Dot Growth, Dot Spread and Press Gain.

Double Bump
To print a single image twice so it has two layers of ink.

Double Dot Halftone
Halftone double burned onto one plate from two halftones, one shot for shadows, the second shot for midtones and highlights.

Doubling
Blurring or shadowing of an image when printed. Doubling may be caused by problems with paper, cylinder alignment, blanket pressures or dirty cylinders.

Dry Back
Printed ink colours become less dense as the ink dries.

Emboss
To press an image into paper so it lies above the surface. Also called Cameo and Tool.

End Sheet
Sheet that attaches the inside pages of a case-bound book to its cover. Also called Pastedown or End Papers.

Fake Duotone
Halftone in one ink colour printed over screen tint of a second colour. Also called Dummy Duotone, Duplex Halftone, Flat Tint Halftone and Halftone with Screen.

Fast Colour Inks
Inks with colours that retain their density and resist fading as they’re used.

Felt Side
Side of the paper that was not in contact with the Fourdrinier wire during papermaking, as compared to wire side.

Film Gauge
Refers to the thickness of a film. The most common gauge for graphic arts film is 0.004 inch.

Fine Paper
Papers made specifically for writing or commercial printing, as compared to coarse papers and industrial papers. Also called Cultural Papers and Graphic Papers.

Fine Screen
Screen with ruling of 150 lines per inch or more.

Flood
To print a sheet completely with an ink or varnish. Also called Painting the Sheet.

Fogging Back
Used to make type more legible by lowering the density of an image while allowing it to show through.

Form Roller(s)
Roller(s) that come in contact with the printing plate, bringing it ink or water.

Fountain Solution
Mixture of water and chemicals that dampens a printing plate to prevent ink from adhering to the non-image area. Also called Dampener solution.

Freesheet
Paper made from cooked wood fibres mixed with chemicals and washed free of impurities. Also called Woodfree Paper.

Full-Range Halftone
Halftone ranging from 0% coverage in its highlights to 100% coverage in its shadows.

Full-scale Black
Black separation with dots throughout the entire tonal range of the image. Also called Full-Range Black.

Ghosting
Chemical ghosting is the transfer of a faint image from the front of one sheet to the back of another. Mechanical ghosting refers to the faint image appearing as a repeat of an image on the same side of the sheet. Or, a printed image appearing too light because of poor ink coverage.

Grade
Term used to distinguish printing papers, but it can also refer to the category, class, rating, finish or brand of paper.

Grain Long Paper
Paper whose fibres run parallel to the long dimension of the sheet. Also called long grain paper and narrow web paper.

Graphic Arts Film
Film that yields high-contrast images suitable for reproduction by a printing press, as opposed to continuous-tone film. Also called Litho Film and Repro Film.

Grindoff
Approximately 1/8 inch along the spine of a book that is ground off gathered signatures before perfect binding.

Groundwood Paper
Usually newsprint made from pulp created when wood chips are ground mechanically rather than refined chemically.

Halo Effect
A faint shadow that surrounds printed halftone dots. Also called Halation and Fringe.

High-Fidelity Colour
Colour that uses 6, 8 or 12 separations, as compared to 4-colour process.

HLS
Abbreviation for hue, lightness and/or saturation. It’s one of the colour-control options often found in software for design and page assembly. Also called HVS.

Hot Spot
When a piece of dirt or an air bubble causes incomplete draw-down during platemaking, leaving an area of weak ink coverage or visible dot gain.

Ink Balance
The relationship of densities and dot gains of process inks to each other and to a standard density of neutral gray.

Ink Holdout
When a paper absorbs ink poorly, drying on its surface. Also called Holdout.

Intaglio Printing
Printing on surfaces with two levels, having inked areas lower than non-inked areas – such as gravure and engraving. Also called Recess Printing.

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Tony Curcio is the editor of Graphic Arts Magazine.