In our business, it is a necessity to know basic paper and printing terms. Use the glossary for a quick reference or browse it to refresh your knowledge.
Select from the general listing below:
back cylinder print
An image unintentionally printed on the backside of the paper. In offset lithography, a printing malfunction, where the ink image is transferred from the blanket to the impression cylinder, and then to the back side of the next sheet of paper run.
back lining
A paper cemented to the backbone of sewed signatures, to bind the signatures and allow space between the backbone of the book and the backbone of the cover.
back pressure
The squeeze pressure between the blanket cylinder and the impression cylinder, usually measured in thousandths of an inch. See also <i>impression</i>.
backbone
The bound edge of a book; also called spine.
backing up
Printing the reverse side of a sheet already printed on one side.
backtrap mottle
This is the printed surface mottle resulting from improper ink tack sequence, with a subsequent color not wet trapping, uniformly on a previous color. See also <i>mottle</i>.
baggy roll (of paper)
Refers to a roll with nonuniform draw; the web width does not uniformly support web tension. There are slack and tight sections across the width of the web, and these are usually caused by stretched portions in the paper resulting from a ridge, rope or other defect in the machine direction. This condition can result in web tension difficulties in subsequent operations.
bar codes
Machine-readable (often OCR), preprinted vertical bars used extensively in labeling, for automated materials handling, inventory control, and point of sale terminals. A multitude of systems exists, usually not compatible with each other and the respective reading devices.
base paper/stock
Paper made for further converting by coating, laminating, etc.
basic
See <i>alkaline sizing</i> and <i>pH</i>.
basic size
The sheet size (dimensions) of a ream of paper (usually 500 sheets) used to determine basis weight See also <i>basis weight</i>.
basis weight
Weight per a selected unit of area of a grade of paper; grammage or "grams per square meter" is used throughout the world and scientifically in the United States; the U.S. uses many different basis weight designations, depending upon the type of paper, including in fine paper, but not limited to: lbs. per 25" X 38"-500 sheets: text, book, offset lbs. per 17" X 22"-500 sheets: writing, bond, ledger lbs. per 20" X 26"-500 sheets: cover lbs. per 24" X 36"-500 sheets: newsprint, tag, tissue, board. The 500 sheets represent the standard "ream" count, and is the basic unit for determining area. Also called substance weight, particularly in the bond or business grades of paper.
Baume' hydrometer
A flotation device used to give the specific gravity, density, and thus concentration of a solution. Can be expressed in Baume' units. See also <i>hydrometer</i>.
bearers
Rings of steel at the ends of offset printing press plate and blanket cylinders, that make rolling contact on impression for meshing of drive gears and for structural support of wide press cylinders. These rings are raised above the cylinder plane to provide a fixed base for determining the packing of plate and blanket.
beater
A large oval tub. See also <i>refining</i>.
beating
See refining.
biocide
See slime.
blade coating
The coating method which uses a knife blade to apply a smooth and level, but non-uniform thickness, of coating to the surface of a sheet of paper. The primary paper coating process.
blade cut
See blade streak.
blade scratch
See blade streak.
blade streak
Also called blade scratch; a very fine line or indentation in the coated surface (less than 1/8" wide), in the machine direction, and varying in length from a few feet to several hundred feet. Streaks can be visible under low angle illumination on the surface or appear less opaque than the general coated area when viewed by transmitted light. This defect can sometimes be observed as an actual cut in the sheet, when the streak is deep enough to sever the sheet. The blade streak, scratch or cut is caused by a piece of fiber, dried coating or coating ingredient, or other foreign material being caught under the blade for a period of time, during the blade coating operation.
blanket
A fabric coated with rubber or other synthetic material which is clamped around the blanket cylinder and which transfers the ink from the press plate to the paper.
blanket creep
See creep.
blanket gap
See cylinder gap.
blanket-to-blanket press
An offset lithographic perfecting press that has no impression cylinders; during printing, the blanket for one side acts as the impression cylinder for the other side, and vice versa. Also called perfecting press unit.
bleach(ing)
The material or the process used to whiten paper pulp; while cellulose fibers are naturally transparent and appear white in Color, wood impurities and staining colorants are encountered in the pulping process giving the fibers a brownish color, as in grocery bags, which are unbleached Kraft pulp. Chemical pulps are bleached in multiple stage processes (3 to 7 stages), with materials like chlorine, chlorine dioxide, hypochlorites, peroxides or ozone (the last 2 being oxygen type bleaching materials).
bleed
1) An illustration that extends to one or more of the edges of a printed piece; bleed illustrations are usually printed 1/8" beyond the planned trim edge(s). 2) Term applied to a lithographic ink pigment, which dissolves in the fountain solution and causes it to be tinted. 3) The discoloration of dyed pulp and paper due to the removal of color by liquid, thereby making it susceptible to staining other materials it contacts.
blinding
In offset lithography, a condition of the plate where the image has lost its ability to accept and/or transfer ink.
blister
An undesirable result that occurs in paper arising from the rapid expansion of moisture in the interior of a well-sealed sheet, when subjected to high drying temperatures; occurs most frequently on a heat-set, web offset printing press. Caused by too rapid or too high temperature drying, or a weak internal bond strength of the paper.
blocking
The sticking together of a stack of sheets or paper in a roll, because of wet ink or coating.
block-out inks
Inks applied to selected areas of some plies of multiple part business forms, such that any transferred image is unreadable in or on that printed area. The block-out ink is usually the same color as the transferred image or darker, so that any image transferred in or on that printed area is unreadable. These inks might be used to block out a price that does not need to be known by an individual ply recipient.
body
A term referring to the viscosity or flow characteristics of an ink or vehicle; an ink with too much body is stiff or is said to have high consistency.
bold face
Heavy line characters or type, in contrast to normal or light-face type; used for emphasis, captions, sub-headings, etc.
bond paper
Originally referred to paper used for printing BONDS and other certificates, but now a generic term applied to business papers; also called writing, or ledger (heavier weight); generally are less opaque than an equivalent weight book paper and are measured on a 17" X 22" basic size.
bonding strength
See plybond.
book papers
Printing papers that are generally used in the graphic arts (exclusive of newsprint and board); also called text or offset; also see cover paper; generally are more opaque than an equivalent weight bond paper and are measured on a 25" X 38" basic size.
breaking length
See tensile.
breast roll
The first or number one roll over which a Fourdrinier wire passes, as the furnish exits the slice.
brightness
In paper, is the amount of light, diffusely reflected from a surface, compared to that which would be reflected from a block of bright Magnesium Oxide; measurement is made with a specific wave length of light (blue), with the surface of an opaque pad of paper being illuminated at a 45 degree angle and the reflection being measured at a 90 degree angle; the human eye sees only reflected light, and brightness influences printed contrast and the amount of illuminating light which is reflected.
broadside
Any large advertising circular.
broke
The term applied to wastage in the manufacture and finishing of paper, in the paper mill. Technically, the wastage that occurs on the paper machine, prior to subsequent finishing operations. Most broke or wastage in the paper mill is returned to the paper machine furnish for reprocessing into saleable paper.
brush finish
A paper that is run under stiff brushes, after coating, to give a high finish.
buckle fold(er)
A fold or folding device which accomplishes a fold in a sheet or signature. The sheet or signature is fed against a constrained flat stop to affect a bend in the sheet, which is completed into a fold by the action of two rollers, pinching the sheet at the point of buckle or maximum bend.
buckles
1) The edge of a roll, usually only part of the diameter, where the paper along that edge is thinner and longer than the balance of the width of the paper on the roll. To compensate for this extra length, it buckles as it is wound. 2) In the binding operation of making books, usually from dry paper, buckles can develop along the bound edge. The paper picking up moisture and increasing in dimensions, resulting in extra dimensions influencing durability causes this and corresponding poor appearance buckles being formed.
buffer
In offset lithography, a material to maintain an acid condition and stable pH in the press fountain solution.
bulk
Measure of the density, or the thickness in relation to the basis weight of a sheet of paper; used in the binding of books and is measured as pages per inch (ppi). Individual sheet calipers do not necessarily total to ppi, because of how the sheets pack together.
bum
In plate making, a common term used for exposing the plate.
burst
A rupture in a web of paper resulting from stresses caused by adjacent areas of high and low caliper, too tight winding of adjacent areas of high and low caliper, or just too tight winding where the wound in tension exceeds the ultimate strength of the paper.
burst strength
See Mullen test.
burst test
See Mullen test.
burster
A business forms handling device for detaching continuous forms at cross perforations.
business form
See form.
butt splice
Formed by trimming the ends of two webs of paper, placing them end-to-end, and pasting a strip over and under to make a continuous web without overlapping. See also <i>splice</i>.
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