Paper Glossary

Paper has a language all its own. Learn how to speak it.


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.
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Archival
Archival papers do not deteriorate (yellow and become brittle) over time. Archival papers are acid-free. They contain calcium carbonate or other buffers for our acidic environment; they contain a very small amount, if any, lignin; and they meet tear criteria.
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Basis Weight
Weighing 500 sheets of any grade of paper in its standard basic size will determine its basis weight. In other words, 500 sheets of 17″ x 22″ 24-pound Bond will weigh 24 pounds. The standard basic size for writing papers is 17″ x 22″, text is 25″x 38″, cover is 20″ x 26″.
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Bond
Originally a term applied to cotton-content paper used for printing bonds and legal documents, and distinguished by strength, performance, and durability. 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.
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Book
General term for papers suitable for the graphic arts. Book paper may be coated or uncoated and is equivalent in weight to text papers.
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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 (like Mohawk Navajo) 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 better black contrast.
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Caliper
Caliper is a measure of paper thickness expressed in thousandths of an inch. The micrometer is used to measure caliper. A paper’s caliper determines the bulk of a given basis weight and is affected by processing done to obtain smoothness and porosity.
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Card Stock
See Cover Paper
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Cast Coated
High-gloss coated paper manufactured by casting the coated paper against a highly polished, heated steel drum.
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Coated Paper
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.
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Conductivity
The electrical property of a sheet of paper that enables it to attract charged toner. Low conductivity can result in poor image quality in digital systems.
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Cover Paper
Also called card stock, these papers are heavyweight coated or uncoated papers with good folding characteristics. Their diverse uses include folders, booklet covers, brochures and pamphlets.
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Cut Size
Papers cut to a small common size, usually 8.5″ x 11″ (“letter size”) and 17″ x 11″.
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Deckle Edge
The rough edges on hand-made and machine-made papers. These edges were originally considered an imperfection but came into fashion with the handcraft revival in the last decade of the 19th century.
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Digital Papers
Papers designed for the specific processes of the emerging digital printing technologies. They are available in popular digital sheet sizes and small rolls.
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Double-thick 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.
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Duplex Paper
Text-or cover-weight papers produced by laminating together two pieces of equal-weight paper. Often “duplex” paper is made with a sheet of white paper laminated to a sheet of dark colored paper.
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Duplexing
The ability of a press or printer to print on both sides of a page without having to manually turn the sheet over.
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Paper and Envelope Converter
A company that constructs various envelopes and other end-use products from parent-size sheets of paper.
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Paper Grade
A system used to classify papers by their common features or content, such as recycled, coated or newsprint papers.
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Paper Manufacturer
A company that makes web, sheet, and/or cut size paper and sells it through paper merchants and paper stores.
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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.
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Paper Stores
A retail outlet often run by a paper distributor, which sells paper in cut sizes to end users. Paper stores typically offer a larger assortment of premium printing papers and envelopes than office superstores, which tend to emphasize papers for xerography.
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PCF
Process Chlorine Free refers to papers that contain postconsumer recycled fiber that was processed without the use of any additional chlorine or chlorine compounds. If these papers also contain a percentage of virgin fiber, the virgin fiber must have been processed without the use of any chlorine or chlorine compounds. Because PCF paper contains recycled-content fibers, PCF paper production can also reduce water, energy and virgin fiber usage.
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Porosity
Often interchanged with air permeability, porosity is a characteristic of a paper’s internal structure. Porosity is the ratio of pore volume to total volume of a sheet. Although rarely measured for premium papers, porosity can indicate how ink will penetrate the sheet.
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Postconsumer Waste Fiber (PCW)
Fiber recovered for papermaking from postconsumer waste paper, which has served its intended use and has been discarded for disposal after passing through the hands of a final user.
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Recycled
Papers that contain postconsumer waste fiber can currently be called recycled. The Federal Executive Order calls for 30% postconsumer waste fiber minimum for uncoated papers, and a 10% postconsumer waste fiber minimum for coated papers.
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Sheffield
The method used to measure the smoothness of paper. The lower the number, the smoother the paper.
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Smoothness
The surface quality of a sheet of paper, related to the flatness of the sheet. Smoothness affects ink and toner receptivity. The Sheffield scale measures smoothness. A higher value typically indicates a rougher sheet.
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Strength
Paper strength is determined more by the nature of its fiber than its thickness. High bursting strength is achieved by forming paper with a tight “weave” of long fibers so that they are both vertical and horizontal within the paper.
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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 color.
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Uncoated Paper
Paper manufactured with no surface coating. There is a wide variety of grades and levels of quality among uncoated papers.
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Vellum Finish
Natural or machine finish, like wove or eggshell.
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Wind Energy
Electric energy that is produced by wind driven turbines. Also called windpower.
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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.
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Writing Paper
Suitable for pen and ink, pencil, laser printing or offset printing. Writing grades are designed for letterheads and corporate identity programs.
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Embossed Paper
Embossing takes place off the paper machine as a separate operation. The embosser uses a patterned roll and pressure to produce an embossed (raised) pattern on a web of paper. Embossing produces a very compact sheet with excellent ink holdout. Linen paper is the most common embossed pattern.
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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.
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Formation
Refers to the uniformity and distribution of fibers within a sheet of paper. In a well formed sheet, solid ink coverage will lay 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.
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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 options.
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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 follow the long side of the sheet) or grain short (they follow the short side). Grain direction should be considered during the design process for best results during printing, folding, and converting.
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Ink Holdout
A characteristic of paper related to its capacity to keep ink sitting on its surface rather than absorbing into the sheet. Better ink holdout produces sharper printed images.
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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 consists 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.
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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. If your job is designated to run through a laser printer, you should specify laser-compatible offset inks.
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Linen Finish
One of the many textured effects that is produced by embossing a web of paper with a patterned roll. Embossing takes place off the machine as a separate operation.
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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.
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Moisture
Paper is made to contain between 4% and 7% moisture. Paper will either pick up or lose moisture to reach equilibrium with the relative humidity in which it is used. 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.
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M-Weight
The weight, in pounds, of 1000 sheets of paper of a given size.
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Non-integrated Mill
A paper mill that does not have an on-site pulp mill and must purchase all the pulp it requires.
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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.
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Opacity
Measure of the percentage of light passing 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.
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