Printing Glossary
A
Acid-free: Acid-free papers are manufactured in an alkaline environment, which prevents the internal chemical deterioration of the paper over time. The addition of calcium carbonate as a buffer also makes the paper resistant to the effects of an external acidic environment. (see ANSI standards)
Antique finish: Rough paper finish created by reducing pressure at the wet presses on the paper machine and with little or no calendaring.
ANSI/NISO: The American National Standards Institute and National Information Standards Organization adopted a standard (Z39.48-1992) for permanence. It is called Permanence of Paper for Publications and Documents in Libraries and Archives. To meet their standard, acid-free papers must measure a minimum pH of 7.5 and meet an established level of folding endurance and tear resistance. http://www.ansi.org
Author’s alterations (AA’s): Corrections or changes made to proofs (bluelines or color proofs) that are not caused by printer error.
B
Base stock: Paper that must be further processed, as in coating or laminating.
Basis weight: The weight in pounds of 500 sheets (one ream) of a standard basic size. For example, the standard basic size for text papers is 25 x 38″. A ream of basis 70 text sheets in that size weighs 70 lbs. The basic size for cover papers is 20 x 26″. Weighing 500 sheets of any grade of paper in its proper basic size will determine its basis weight. In other words, 500 sheets of 17 x 22″ 24-pound Bond will weigh 24 pounds.
Binding or bindery: Process starts after the printer has laid ink on paper. Includes cutting, trimming, folding, collating, stitching, pasting, inserting, etc.
Bit: Short for binary digit, it is the smallest unit of information a computer can interpret. It can indicate only two conditions-black or white, for instance, or on or off.
Bitmap: A computer file in which each pixel contains one bit of image information. Sometimes used interchangeably with raster.
Bits per second (bps): The speed by which a modem can send a file.
Blanket: Fabric-reinforced sheet of rubber used on offset presses to transfer the impression from the plate to the paper.
Blanket cylinder: The cylinder in an offset press that sits between the plate cylinder and the impression cylinder. The inked image is transferred from the plate to the blanket, and then from blanket to paper.
Bleaching: Pulp fibers are bleached to produce pure, stable, permanent, white fibers for papermaking. The kraft or sulfate process is the primary bleaching process used in the United States.
Bleed: An image that is printed to the edges of a page, or the ability of a press or printer to print an image to the edges of a page. A full bleed document is printed on a larger sheet and is trimmed to size, since ink or toner would foul press cylinders or belts if it actually extended off the edges of the paper. Printers typically charge more for bleeds because more paper is required.
Bond: Originally a term applied to cotton-content paper used for printing bonds and legal documents, and distinguished by strength, performance, and durability. Used for letterheads and forms, bond paper may now be made from either cotton, chemical wood pulp, or a combination of the two. Today, writing, digital, and cut-size papers are often identified with the bond scale (see basis weight).
Book: General term for papers suitable for the graphic arts; may be coated or uncoated.
Brightness: Brightness is measured as the percentage of light in a narrow spectral range reflected from the surface of a sheet of paper. It is not necessarily related to color or whiteness. A paper with a brightness of 98 is an extremely bright sheet with almost all light being reflected back to the viewer. Bright white papers illuminate transparent printing inks, giving cleaner, crisper color, and contrasty blacks.
Broken carton: Less than a full carton of paper. Generally sold at a premium due to additional handling and storage costs.
C
C1S: Coated one side
C2S: Coated both sides
Cabinet: Matching components of wedding or announcement lines (invitations, envelopes, reply cards, etc.) are packaged together and sold in “cabinets.”
Caliper: Caliper is a measure of paper thickness under specified conditions expressed in thousandths of an inch. The micrometer is used to measure caliper.
Card stock: Also called cover stock. Stiff, heavy weight paper for items like post cards, booklet covers, and menus that need bulk and rigidity. Specified in points (caliper thickness, such as 10 pt.) or basis weight (such as 80 lb. Cover).
Case binding: Hardbound book covers are called “cases” which are chipboard covered on the outside and edges with cloth, leather or other material.
Cast coated: High-gloss coated paper manufactured by casting the coating paper against a highly polished, heated steel drum.
Chain lines: Watermarks in laid paper that run parallel to the grain.
Charge: Either a positive or negative property of electricity, charges are used in
Chlorine-free paper: Papers made from pulps that have been bleached with agents, like oxygen, other than chlorine.
Click: Term for one revolution/one copy on a digital copier.
CMYK: Cyan, magenta, yellow and black, are the process colors of toner or ink used in offset and digital printing. The colors overlap and appear to mix visually to reproduce a complete spectrum of colors.
Coated paper: Made with a surface coating, which allows for maximum smoothness and ink holdout in the printing process. Coated papers are available in a range of finishes from dull to matte, and gloss.
Collate: The ability of a printer, copier or press to assemble sheets in a proper order, for instance, for binding.
Conductivity: The electrical property of a sheet of paper, which enables it to attract charged toner. Low conductivity can result in poor image quality in digital systems.
Contrast: The difference in tonal value between light and dark areas within an image.
Converter: Company that converts paper from its original form into envelopes, announcements, writing pads, or small, prepackaged quantities for home office use.
Corona: The element that cleans the photoconductive drum or belt of an electrophotographic system after an image is printed.
Cover paper: Also called card stock, these papers are heavyweight coated or uncoated paper with good folding characteristics. Their diverse uses include folders, booklet covers, brochures and pamphlets.
Cut size: Papers cut to a small common size, usually 8.5” x 11″ and 17″ x 11″.
D
Data compression: The process of compressing the information in a computer file into a format that uses less computing space. When the file is to be used, it must be decompressed.
Deckle edge: Produced in hand-papermaking by drainage under a wooden frame surrounding the hand mould. The rough edges on hand-made and some machine-made papers were originally considered an imperfection. The deckle edge came back in fashion with the handcraft revival in the last decade of the 19th century.
Densitometer: Instrument used to measure printed ink density to determine consistency throughout a press run.
Digital papers: Papers designed for the specific processes of the emerging digital printing technologies. Unlike traditional offset printing, the digital environment is centered in quick turnarounds, short runs, and the ability to vary printed information within the run.
Digital printing: Printing in which an image is applied to paper or another substrate directly from a digital file rather than using film and/or plates.
Digital proofing: Proofing directly from digital files, as opposed to using film to create proofs.
Dimensional stability: Property of paper that measures its ability to retain its dimensions under the stress of production and humidity changes. Poor dimensional stability adversely affects registration on the printing press.
Direct to plate: A process in which printing plates are imaged from a digital file instead of film; this process can take place on the press, as with the Heidelberg DI process.
Distributed printing: Also called distribute and print. Electronically forwarding a file and then printing the job at the point of delivery.
Dot: Basic halftone printing unit. Dot gain is the tendency for printing dots to expand due to ink absorption into the paper.
Double-thick (D.T.) cover: Stiff, durable cover papers produced by laminating together two pieces of equal-weight paper. The resulting sheet is heavy and strong, with excellent printing and folding characteristics.
dpi: The dots per inch an output device is capable of producing, or the measurement of dots per inch in a particular image. An industry standard rule of thumb is the input dpi is approximately twice the output lpi. For example 133 lpi = 266 dpi.
Dummy: Carefully assembled pages of actual paper stock represent exact form of final printed piece. Helps printer and client visualize written specifications. An important guide for printer and bindery.
Duotone: Two-color halftone reproduction from black and white original.
Duplexing: The ability of a press or printer to print on both sides of a page without having to manually turn the sheet over.
E
ECF: Elemental chlorine free. Pulp bleached using chlorine dioxide (a salt) rather than with the more reactive chlorine gas. ECF bleaching is the preferred method of most U.S. pulp mills.
Electrophotography: A printing or copying method, which uses an electrical charge to create an image on a photoconductive surface. Toner is attracted to the charged area and then transferred and fused to paper.
Electrostatic printing: A printing process that uses an electrostatic charge to create an image.
Embossed paper: Finish imparted to a web of paper in an embossing machine. Process is separate from the main papermaking process and involves running a web of paper between a steel embossing roll and a cardboard backing roll. Irish Linen is an example of embossed paper.
EPS: Encapsulated PostScript, a standard file format for high-resolution PostScript images. It usually has two parts: the PostScript code (which tells the computer what to do) and a PICT image (for on-screen viewing).
F
Felt: Woven textile, originally wool but now usually synthetic, used to carry the web while moisture is pressed from it. While on the paper machine, the felt acts as a support for the paper web. Felts, if they are rough, can impart a felt finish to the paper.
Felt-side: The top side of the paper web, which comes in contact with the papermaking felt.
Flecked, flocked, and fibered: Terms commonly used to describe decorative fiber additives to text and cover papers. Colored cotton and/or rayon fibers are added to the paper stock to create the look of hand-made paper. Other additives include jute fibers, and colored bits of paper stock.
Folio: In paper making, the term for full-size sheet of paper: e.g. 23 x 35″ or 26 x 40″. In printing it refers to a folded sheet (2 leaves — four pages) Also a term for page numbers.
Form: Assembly of pages on a printed sheet. When folded, the form is called a signature.
Formation: Refers to the uniformity and distribution of fibers within a sheet of paper. In a well formed sheet, solid ink coverage will go down smoothly. A poorly formed sheet will exhibit a mottled appearance when printed. Formation can be checked by holding the paper up to a light source: A well formed sheet appears uniform, while in a poorly formed sheet the fibers appear as clumps, giving it a cloudy look.
Front-end system: A computer system attached to a printer or copier, which also handles other operations, including storage and page composition.
G
Genuine felt finish: A finish applied to paper by means of marking felts while the paper web is still very wet. These felts impart their distinctive textures by gently rearranging the paper fibers. This creates a soft, resilient, textured surface suitable for printing and relief operations.
Grain direction: As the paper web is carried forward on the machine, the majority of fibers orient themselves in the machine direction. When the web of paper is sheeted, the sheets will be grain long (fibers that run parallel to the long side of the sheet) or grain short (they run parallel to the short side). Grain direction should be considered during the design process for best results during printing, folding, and converting. In sheetfed printing, paper is generally printed grain long. Folds are smoother if they go “with the grain.”
Grammage: Basis weight of paper stated in metric terms. See Basis Weight for comparison chart.
Guillotine-trimmed: Stacks of paper cut or trimmed to desired size on a device that looks like a French guillotine. Care should be taking when trimming paper as a dull blade can result in cutter dust or scuffs and roll backs.
H
Halftone: The result of photographically or electronically converting a continuous tone image-like a photo or shaded drawing-into a series of dots which offset presses and most digital printers can reproduce on paper. The various sizes of dots trick the eye into seeing shades of gray.
I
Imposition: The arrangement of pages on a press sheet so they are in the proper order when folded.
Impression cylinder: The cylinder on a press or printer that brings the sheet of paper into contact with the blanket cylinder so that the inked or toner image can be transferred to paper.
Impressions per minute/hour: The number of printed units a press, printer or copier can print in a minute or an hour.
Ink holdout: A characteristic of printing and paper related to the capacity to keep ink sitting on its surface rather than absorbing into the sheet. Better ink holdout produces sharper printed images.
Ink jet: A type of printer that sprays droplets of ink onto paper to form an image. Continuous inkjet printers spray a continuous stream of ink which is electronically controlled to print an image. Drop-on-demand inkjet printers shoot out single drops of ink as needed.
J
Just-in-time printing: Storing documents digitally and then printing only the number needed at any particular time. See on-demand printing.
L
Laid: A linear pattern which is applied by a dandy roll while the paper is still very wet, to mimic the effect of some hand-made papers. The laid dandy roll is comprised of wires that run parallel to the roll’s axis (laid lines), and chain lines, which connect the laid lines and run in the grain direction.
Laminated: Paper made by fusing two lighter weight sheets together to create a new sheet of desired thickness. The resulting paper is especially strong.
Laser: Acronym for Light Amplification by Stimulated Emission from Radiation. An intense, focused beam of light used in many imaging systems to produce images through electronic impulses.
Laser Paper: Very smooth, low-moisture papers manufactured in cut sizes for laser printers and office duplicating equipment. Low moisture prevents paper curling from high heat in laser printers. Note: If your job is designed to run through a laser printer, you should specify laser-compatible offset inks.
Laser printer: A desktop printer which uses a laser beam to create an image on a photoconductive drum. Dry toner is attracted to the charged area and is fused to paper with heat and/or pressure.
LED Light emitting diode: lossless compression A method of compressing electronic data so that no information is lost in the compression process. It is not as effective in reducing file sizes as lossy compression.
Linen Finish: One of the many textured effects that is produced by embossing a web of paper with a patterned steel roll. Embossing takes place off the machine as a separate operation.
Long grain: Grain direction of sheet runs parallel to longest sheet dimension.
Lossy compression: A method of compressing electronic data that selectively discards information in order to dramatically decrease file size. The lost information may or may not be noticeable. It is more effective in reducing file sizes than lossless compression.
lpi: Halftone screens are measured in lines per inch. A low lpi indicates a coarse screen ruling; higher lpi’s indicate finer screens.
M
M: Paper industry abbreviation for 1,000.
Machine felt finish: Rubber marking rolls apply a felt-type finish to paper right before the dryer section. This technique yields a softer surface than embossing, and better bulk. The surface is slightly harder than with a genuine felt finish. Though less natural in feel, a machine-felt texture is more economical and provides greater ink holdout because of its compact surface.
Making order: Custom made size, color, basis weight or pack. Mills generally have different minimum quantities for different types of making orders. Close coordination between printer, merchant, mill is essential for making orders.
Mill item: Paper stocked by the mill that is not stocked by local merchant. Generally delivered in 2 to 5 business days depending on availability and your location.
Moisture content: The amount of moisture found in a sheet of paper. If the moisture content in a sheet is too high or too low, the paper can curl or build up static, which affects the way it runs through a press, printer or copier.
M-weight: The weight, in pounds, of 1000 sheets of paper of a given size.
Make-ready: Work done to a press to make it ready for printing a particular image, including loading plates, paper, ink and toner, as well as adjustment of color and registration.
O
Offset paper: Uncoated paper designed for use in offset lithography. Important properties include good internal bonding, high surface strength, dimensional stability, lack of curl, and freedom from foreign surface material.
Offset printing: A printing process that uses an intermediate blanket cylinder to transfer an image from the image carrier (the plate) to the substrate (usually paper).
On-demand printing: Term for new business developing around short-run color printing. Small quantities of high-quality color printing can be delivered “on demand” wherever and whenever required.
On the fly: A phrase often used in digital printing to describe a press’ ability to print variable data as it is operating, without being shut down for a new make-ready.
Opacity: Measure of the percentage of light passage through a sheet of paper. The more opaque a paper is, the less show-through there will be from printing on the sheet below. Basis weight, brightness, type of fibers, fillers, coatings, and formation all influence opacity. Generally, opacity and brightness are inversely related to each other: the brighter the paper, the less opaque. Other factors that affect opacity are bulk, surface smoothness, and shade.
Optical brighteners: Also called fluorescent dyes, these are used extensively to make very high bright, blue-white papers. They absorb invisible ultraviolet light and convert it to visible light on the blue/violet end of the spectrum.
Output: Electronic data transferred to another device, such as a storage drive, printer or press.
P
Paper and envelope converter: A company that constructs various envelopes and other end-use products from parent-size sheets of paper.
Paper grade: A system used to classify papers by their common features or content, such as recycled, coated or newsprint papers.
Paper manufacturer: A company that makes web, sheet, and/or cut size paper and sells it through paper merchants and paper stores.
Paper merchant: A liaison between the paper manufacturer and the paper buyer who offers a number of lines of papers and can offer advice to buyers on the best sheets to specify for particular jobs. Merchants sell paper and envelopes to printers.
PCF: Process chlorine free. A term currently used to define paper made from a combination of chlorine free (TCF) virgin pulp and recycled fiber that is de-inked using a non-chlorine bleach such as oxygen or peroxide.
PDF Portable Document Format: A file format, which allows a file, created on one computer platform to be viewed and printed intact by computer users on a number of different platforms. Created by Adobe Systems for its Acrobat products.
Perfect binding: Bindery method where all pages are trimmed to single sheets. They are clamped together and a cover is wrapped around the spine. The pages are attached to the cover using an adhesive.
pH: Degree of acidity or alkalinity measured on a scale of 0 to 14 wit h7 being the neutral point. pH is important in paper permanence but also in proper functioning of fountain solutions in offset printing.
Pica: Typographic measurement. There are 12 points to a pica and approximately 6 picas to an inch.
PICT: Standard file format for graphics files on the Macintosh. Can contain both object-oriented and bitmapped graphics and is the standard format for all graphics that are cut or copied to the clipboard.
Plateless printing: A printing process in which an image is transferred directly to paper or another substrate without the use of a printing plate.
Point: In measuring type, 1 point is 1/12 of a pica or 1/72 of an inch. In measuring the thickness of paper stock, a point is 1/1000 of an inch. 10-pt card stock, for example, is 10/1000 or 0.010 in.
Porosity: The characteristic of a paper’s surface that lets air pass through it.
PostScript: A page description language that describes in detail how images and text on a printed page should look. PostScript code is translated by a raster image processor-or RIPped-before it can be used by an digital printer or press.
Print on demand: The ability to print only the documents you want in the quantities you want, when you want.
Process color: The colors of ink or toner-cyan, magenta, yellow and black-used in four-color offset and digital printing.
R
Raster: An electronic file type, which mathematically describes points on a grid. Also called bitmap. The finer the grid, the higher the resolution, and the larger the file size. Low-resolution files are smaller in file size than high-resolution files.
Raster image processor (RIP): A device which interprets a page description language (such as PostScript) that contains a file’s instructions for printing a page. The RIP converts the instructions into dot patterns that the printer can create to image a page.
Ream: 500 sheets of paper.
Registration: Placing two or more images into alignment on press. An image that is “out of register” has some of its color or black layers out of alignment.
Resolution: Also called res (as in low-res or high-res). Measured in dpi or pixels, resolution indicates the degree of image sharpness that can be produced on a particular press or printer. The higher the resolution, the larger the file, and the better the quality of the image will be. For low-end printers, resolution is measured in dpi; for example, a 600 dpi laser printer. For high-end printers and scanners, however, resolution is counted vertically and horizontally, 1440 x 720 dpi, for instance.
RIP: See raster image processor.
Recycled: Papers that contain postconsumer fiber can currently be called recycled. The Federal Executive Order calls for a 20% postconsumer fiber minimum for uncoated papers, and a 10% postconsumer fiber minimum for coated papers.
Reply Card: Paper manufactured to specific caliper defined by the U.S. Postal Service for Business Reply Card (BRC) mailings. 7 Point meets this requirement.
S
Saddle stitch or saddle-wire binding: Industrial stapler is used to insert a staple or two into the center fold of a signature to produce a book or brochure.
Server: On a computer network, a server is a CPU or other unit that handles printing, communication tasks, filing, and other jobs, in order to free up other computers on the network for other tasks.
Set off: Also called off set. Transferring or smearing of ink from freshly printed press sheets to another surface. Printers often add a varnish or aqueous coating in line to avoid set off of printed sheets in bindery operations.
Sheetfed press: A printing press that is fed with individual cut sheets of paper.
Show through: Printing that is seen by looking through a sheet of paper that is not opaque enough.
Signature: Section of a book obtained by folding a sheet of paper into 4, 8, 12, 16, or 32 pages. Signatures always contain increments of four pages.
Smoothness: The surface quality of a sheet of paper, related to the flatness of the sheet. Smoothness affects ink and toner receptivity. Smoothness is measured by the Sheffield scale. A higher value typically indicates a rougher sheet. For example, coated paper may have a smoothness of 10-30, whereas vellum offset may have a rating from 200-250.
Spiral binding: Wire in spiral form is inserted in specially drilled holes along the binding edge.
Substrate: The material upon which something is printed, usually paper. SWOP Acronym for Specifications for Web Offset Publications.
T
Text and Cover Papers: A class of high-quality uncoated papers in a wide variety of colors and textures. Text is usually made with a matching or coordinating cover.
TIFF: Tagged image file format. A file format used for storing and exchanging bitmapped or raster images, such as are created in paint or photo manipulation programs.
Toner: Tiny plastic resin particles that are used in the electrophotographic printing process to form an image. Toners can be dry or liquid. For both types, the toner particles are charged and applied to the image area on a photoconductive drum or looped belt. Then it is applied and fused to paper.
Translucent paper: Paper made by beating the paper fibers until they are very short and translucent. Some translucent papers are transparentized using chemical treatments. Originally used for tracing paper, it is specified for flysheets and other decorative purposes in commercial printing. Translucent papers are fairly difficult to work with, as they are fragile with low dimensional stability. However they provide interesting visual contrasts and have been used successfully in a wide variety of applications.
Trap: How well a printed ink can accept the next ink printed compared with how well blank paper accepts that ink. The thickness of ink application; the drying time of that ink; the printing ink sequence; and the settings of the press all affect trap.
Trapping: The process of overlapping two adjoining colors in an image so that holes are not left in the image by the normal registration variations of the printing process. There is usually some debate about who should handle trapping-the designer or the printer-so it’s important to discuss the matter before any files are created.
U
Uncoated paper: Paper manufactured with no surface coating. There is a wide variety of grades and levels of quality among uncoated papers.
W
Waterless printing: A process on which fountain solution is not necessary. Non-image areas of the printing plate are treated with silicone so that they reject ink.
Watermarks: Designs formed in fine wire or in low-relief metal castings and sewn onto the dandy roll. The resulting thick and thin areas make the watermark slightly more translucent than the rest of the sheet. Watermarks were historically used to convey a sense of quality in letterhead papers.
Web press: A printing press or printer that is fed with a continuous reel of paper.
Wire Side: The side of the sheet that rests on the paper machine wire as it moves through the wet end, as distinguished from the felt or top side.
Wove: Most common plain surface paper used today. The opposite of Laid, it refers to the wire pattern created by a “wove” dandy roll without chain lines.
Writing Paper: Suitable for pen and ink, pencil, typewriter or printing. Similar to bond papers, writing papers characteristically have a softer surface than bonds, which are made for mechanical erasing. Writing grades are designed for letterheads, corporate identity programs, and office copiers.
X
Xerography: An electrophotographic process that electrostatically charges an image on a photoconductive drum or belt. The charge attracts toner, which is then fused to paper.