Glossary of Paper Terms

A standard sheet size used to establish basis weight for a given grade of paper. The standard size varies, depending upon the grade or type of paper and is related to the traditional end usage.

The weight in pounds per ream of paper cut to its basic size. A standard ream is defined as 500 sheets.

Durable, strong writing paper originally used for bonds, now used for letterhead and other stationary.

Brightness is the percentage of light at a certain wavelength (457 nanometers) that is reflected from the surface of the paper and is related to how light or dark the sheet appears. High brightness papers give greater contrast with black inks and a more vivid appearance of ink colors. Low brightness papers are traditionally used in book printing or limited use read and dispose.

Heavyweight or thick paper (usually 6pt or higher) commonly used for filing or mailing.

A measure of the strength of paper to withold pressure.

The thickness of a sheet of paper, expressed as thousands of an inch, or points. 

Collectively, a set of two or more papers that are engineered to transfer images through applied pressure from the top sheet to one or more sheets below, without the use of a carbon sheet.

Paper that is meant to be used as a base material to be altered through a conversion process to create another paper product.  Examples include envelopes, paper bags, tablets and forms.

Also referred to as card stock; a heavyweight paper designed to be used as booklet, magazine covers or brochures.

The tendancy for a sheet of paper to bend, either by design (as in the case of office papers) or undesirably (due to improper balance of moisture within the sheet).

The printing technique whereby documents or images are transmitted using a electronic file transferred from a computer to or other digital storage device to the printer, either a digital press or an inkjet device. Digital printing is best suited for smaller runs.

Paper made specifically for the purpose of converting into envelopes. 

The means by which a particular basis weight can be compared to another paper with a differing basic size. It is the basis weight expressed in terms of a different basic size. 

The characteristics of the surface of a paper meant to convey smoothness or texture. Examples include Smooth, Super Smooth, Vellum, Wove and Antique.

The number of double folds a paper will withstand without rupture, under constant tension.

Formation is judged by transmitting light through the sheet and looking at its structure and degree of uniformity. Paper with good formation prints with less mottling and has more uniform opacity.

Paper that contains less than 10% groundwood or mechanical pulp.

Refers to the alignment of fibers in the direction of their flow on the paper machine. Folding and scoring work best when done in the paper’s grain direction. Grain also affects tear strength, stiffness and dimensional stability.

A sheet of paper in which the fibers are aligned parallel to the long edge. A longer dimension noted last indicates grain long — 11″ x 17″.

A sheet of paper in which the fibers are aligned parallel to the short edge. A shorter dimension noted last indicates grain short — 17″ x 11″.

A heavyweight card stock typically used for folders and cards.

Refers to the printing technology where a digital image is reproduced through the spraying of microscopic liquid ink (or dye) droplets onto the surface of the paper.

A strong paper made from sulfate pulp and typically used to make envelopes and bags.

Paper suitable for checks or other business documents that can be printed with magnetic ink. Documents can then be read by data processing equipment through magnetic ink character recognition.

This is the amount of moisture contained by paper, expressed as a percentage of its total weight. Uniform moisture is a necessity in all grades of paper. 

The process by which multiple impressions of an original image are produced by transferring inks from a plate to rubber blankets or rollers, then to the surface of the print media. Offset printing is best suited to larger runs.

The ability of paper to obstruct light transmission and the show-through of printing. It is particularly important in two-sided printing. It also affects readability and overall appearance. Opacity is improved by scattering, absorbing or reflecting light. Fillers such as titanium dioxide and calcium carbonate scatter light, while blue and violet dyes absorb it. 

Paper characterized by a high level of opacity and a minimum amount of show-through.

Refers to the resistance paper has to air permeation. A higher number means less porosity.

The extent to which the a particular sheet performs with regard to ink receptivity, uniformity, smoothness, compressibility and opacity.

Fiber derived from previously manufactured and consumed paper, having been discarded after its original use life.

The amount of moisture in the air expressed as a percentage of the maximum amount of moisture the air could hold at a given temperature. Ideal printing conditions call for a RH at 45%.

The extent to which paper can run in printing, converting and other processing equipment, without jamming, breaking or otherwise causing mechanical failure.

Internal sizing in the paper affects absorbency, strength and permanence. External sizing improves resistance to water, ink and other fluids, seals down surface fibers and improves surface strength. Typical sizing agents are rosin, glue, gelatin starch resins, waxes, etc.

The evenness or lack of contour in the surface of an uncoated sheet.

The extent to which paper resists bending.

A quality measured by tests for burst, tear, tensile and folding strength, in which each measures the ability of the paper to withstand forces in different directions.

A heavy, durable card stock commonly used for tags, cards, menus and folders.

The Technical Association of the Pulp and Paper Industry, a well-regarded professional organization who has established recognized technical standards and testing procedures pertaining to the manufacture and use of pulp and paper.

A measure of the amount of force  required to tear paper.

The maximum force required to break a strip of paper.

The widest sheet of finished paper that can be made on a paper machine or the unneeded waste cut from a roll of paper during converting. Waste is minimized by utilizing the fullest width of the sheet possible (trimming), into finished goods.

A paper finish characterized by a slightly rough or toothy surface. Vellum finish should not be confused with vellum paper, which is a transluscent paper used primarily for drafting.

Fiber derived from a wood source used for the first time in paper making, not recycled.

The extent to which the surface of the paper reflects light of all wavelengths throughout the visible spectrum.

A smooth, even paper finish that displays no texture.