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Shown below are the definitions for: D
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dampeners The rollers (mechanical devices) that carry the fountain solution from the press fountain to the lithographic plate.
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dampening solution See "fountain solution"; also called dampening etch (particularly in reference to fountain solution concentrate).
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dancer roll Usually, a weighted roll that rides on a web of paper between two fixed points (for example, between an unwinding roll of paper and an impression or coating nip) to take up slack and maintain a uniform web tension.
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dandy roll On the paper machine, impresses the still wet web of paper to smooth the formation, reduce foam bubbles, and to impress a pattern if desired; with raised areas on the wire covered dandy roll, can give a watermark or laid pattern; with recessed areas, can also give a watermark like pattern called a "shadow mark"; the raised or recessed patterns on the dandy roll result in a difference in transparency and usually a desired effect, if light is viewed through the sheet.
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de-inking The mechanical or chemical removal of printing inks and other foreign materials from paper, so that the cellulose fibers can be reused or recycled.
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deciduous Leaf bearing trees that shed them with the seasons, like oak and maple; also known as "hardwood". Pulps made from this type of tree give cellulose paper making fibers that are short, thus "short fiber".
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deckle edge The untrimmed, feathered edge of the dried paper from the paper machine; see "deckle" and "feather".
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deckle In paper making, the width of the wet sheet as it comes off the wire.
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delaminate See "plybond".
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delivery The printing press mechanism that handles the paper, after it is printed. Printing presses "deliver" the printed product as flat sheets, folded sheets (signatures), finished products or rewound rolls.
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densitometer Instrument used to measure the optical density of an image or color; optical density is the intensity of the color or printed image, usually (but not always) referenced to black and/or white.
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desensitize 1) In lithographic printing plates, making the non-image area of the metal plate non-receptive to ink. The main desensitizing material is usually a gum. 2) In carbonless paper, the over-printing of the CF (receiving) surface so as to eliminate its ability to develop an image from the CB surface.
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digester The large pressure vessel in which wood is pulped (cooked), to extract the cellulose fibers; can be continuous or batch process digesters.
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dilatant The property of some inks and coatings to become less fluid (higher viscosity) when worked (stirred), as a result of separation of the vehicle phase from the suspended materials; this dilatancy phenomenon is not always reversible, once the separation has occurred; also see thixotropic.
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dilitho See "direct printing".
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dimensional stability Ability to maintain size under conditions of varying moisture or humidity; the property of a sheet of paper which relates to its constancy of dimensions under conditions of different relative humidities.
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direct printing Any printing where the ink is transferred directly from the plate to the paper; most lithographic printing is "offset", i.e., a blanket is utilized to transfer the ink from the plate to the paper. Dilitho is the abbreviated term for direct lithography.
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dished roll See "telescoped roll".
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disk refining See "refining".
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doctor Usually a blade used on many types of equipment for coating (see blade coating), for metering (removing excess ink from a gravure cylinder or plate), or for keeping the surface of a roll clean.
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dog ear See "turnover".
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dot gain The gain in size of the printed dot, as a result of the ink, paper, printing pressure, prepress operation, or any combination of these. Since the dots printed are larger than planned, this can be a defect evidenced by darker tones and/or different hues.
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dot The individual printing element or spot in halftone printing.
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doubling In printing, the appearance of a latent, second or ghost like image of the original on the printed piece, or the appearance of a "slur" or blurring of the image. Doubling can be the result of "creep", or even a mechanical feeding problem on the press, where the image has moved its position on the blanket (resulting in a misregister from unit to unit). If the cause of the doubling is due to "creep", the latent image will generally disappear as the latent ink image is removed from the repositioned blanket. Variability (come and go) of the latent doubling image is usually due to a mechanical press or feeding problem. Paper distortions can also cause doubling.
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drag mark See "coating streak".
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drawdown The application (by a blade or a bar) of a thin film of coating or ink to a piece of paper; it is used as a test method for coating or ink characteristics (such as shade, color strength, coating strength, or other simulation testing).
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draw 1) In guillotine trimming of paper, the displacement of the cut sheet in a clamped stack by the thickness of the knife; can result in inaccurately cut paper. 2) The tension on a paper web between sections of a piece of equipment, such as a paper machine, coater, or printing press.
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driers See "dryers".
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drilling Piercing of stacks of paper in a precise manner; loose leaf notebook paper is an example of drilled paper, using a hollow point drill.
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dry back The term applied when the density and/or gloss of the wet, freshly printed ink film decreases after drying, to a greater extent than was anticipated. It is generally related to an overly absorbent paper surface, or a poor ink-paper choice and match.
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dry end That part of the paper machine where the paper is dried; the last sections of the machine.
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dry offset See letterpress printing; refers to the use of a letterpress plate or cylinder on an offset press, i.e., transfers the ink from the plate to the paper on an intermediate blanket cylinder. Also called letterset.
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dry trapping See "trapping".
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dryers 1) The pieces of equipment used to dry the paper during manufacture or coating, or during printing (large, steam heated rotary cylinders, hot air dryers, or direct radiant heat impingement). 2) Various materials added to ink to promote or speed (catalyze) ink drying by oxidation/ polymerization; also spelled driers.
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drying of inks Printing inks dry in a number of different ways, and often in a combination of these: absorption, oxidation, polymerization, evaporation, precipitation, solidification (such as cooling of a hot, melted material) and radiation curing. All of these are mechanisms for turning a fluid, mobile ink into a relatively immobile image.
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drying oils Oils which posses the property of hardening to a tough film by oxidation and polymerization (like linseed oil).
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dull finish See gloss; any finish lacking gloss and/or luster; generally refers to an intermediate gloss of coated papers or to printed ink films.
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dummy A preliminary layout or presentation to show the style, form, size or shape of a printing job.
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duplicator Earlier the term referred to "spirit duplicators", but has now come to mean (generally small) sheet-fed lithographic presses that often as not are for relatively short runs (up to 10,000).
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dust Loose particles of fibers, filler, or coating materials appearing on the edges of a skid, lift, or roll of paper; this dust can interfere with the quality of the printing, particularly if on the sheet or web surface.
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