The A-Z of Label printing (L-P)

Laser Printing
Also known as electro-photographic printing, a process where light, generated from either a laser or diode, creates a static charge on a photographically-sensitive cylinder. The charged cylinder attracts toner, which is subsequently transferred to a printable surface, creating an image. See also:

Latex Paper/Latex-Impregnated Paper
Paper saturated with latex during its formation making it more resistant to moisture and abrasion, more flexible, and more durable.

The stringy appearance of adhesive when a pressure sensitive label is separated from a substrate or its release liner. It can also occur when the matrix is removed from a die cut pressure sensitive material.

Letterpress Printing
A printing process in which ink is applied to a material from the raised portions of printing plates or from foundry type.

Life Cycle
The length of time that a label is to be used before it is ultimately discarded.

Lift Tab
A label edge that is not coated with adhesive and thereby, allows for easy removal of the label from the release liner. It is frequently used for order picking labels.

Line Art
Black and white artwork that can be reproduced as is.

A paper or film that is a carrier for pressure sensitive labels. Typically, it has a silicone coating to allow easy removal of the label. See also: Backing, Carrier, Release Liner.

Lithographic Paper
A paper suitable for lithographic (or offset) printing.


Machine Direction
The direction of paper in its forward movement through a paper handling machine or printing press.

Machine Finish
See: Calendar Finish.

Machine Readable
Refers to the scanning of bar code symbology by a laser scanner or similar device.

The face material and adhesive layers of a pressure sensitive construction surrounding a die cut label which is typically removed after die cutting.

Matte Litho
A litho paper with a satin finish -- between high gloss and dull finish -- that is ideal for bar code printing.

The property of a material that causes it to shrink or return to its original dimensions after being distorted, die cut, or subjected to temperature change. For example, vinyl (being very flexible) has more memory than polystyrene.

Metallized Film
A plastic or resinous film that has been coated on one side with a very thin layer of metal.

Metallized Paper
Paper that has a thick deposit of metallized particles that resemble a layer of foil. Metallized paper offers reduced stiffness and better flexibility than metallized film and has an appearance similar to laminated foil papers.

The movement of one or more of the components of a pressure sensitive adhesive to either a substrate or face material.
The movement of one or more of the components of the face material and/or the substrate into the adhesive and/or ink.
The uncontrolled spread of ink due to improper printing or curing.

Moisture Content
The moisture present in a material. This is particularly important in liners.

Moisture Equilibrium
The condition reached by a material when it shows no change in weight, in relation to the amount of moisture absorbed or desorbed by the material.

Moisture proof
The property of a material which makes it virtually impervious to moisture. Tyvek® is a moisture proof material.

Mottled Surface/Mottling
Non-uniform appearance or colouring of a face material -- blotching.

Multiple-Web Construction
A construction consisting of two or more face materials and/or adhesives on the same liner. Example: EDP face material with permanent adhesive and non-pressure sensitive card stock side by side.


Natural Aging
The change, if any, in a material occurring from exposure to normal environmental conditions.


OCR/Optical Character Recognition
An information processing technology that involves conversion of imprinted or written data to another language and medium.

The partial transference of ink from a freshly printed surface to an adjacent surface - as that of another sheet of paper.

Offset Printing
A printing process in which a right-reading image is printed from a plate onto a blanketed cylinder, this mirror image is then pressed against a printing surface thus creating the desired, final image. The term offset applies because the printing plate never comes in contact with the printing material as it does in letterpress printing.

the measure of the amount of light that can pass through a material.

Orange Peel
The mottled or textured appearance of a label that can occur from air bubbles trapped between a laminate and face material.

See: Clear Coat, Lacquer, Protective Coating, Top coat/Top Coating, Varnish.

The application of a clear film to label material for the purpose of protection or to enhance visual quality.


Pattern Coated Adhesive
See: Adhesive: Pattern Coated.

Pattern Gummed Adhesive
See: Adhesive: Pattern Gummed.

Patterned Release Coating
See: Release Coating: Patterned.

Peel Adhesion
Peel adhesion is the force required to remove a pressure sensitive label from a standard test surface at a specified angle and speed after the label has been applied according to specified conditions. See also: Adhesive Strength.

The change in appearance of the face material due to movement of one or more components from the adhesive or the substrate. See also: Migration, Plasticizer Migration.

Refers to a series of small incisions made in a material to facilitate tearing or folding along a pre-determined line. They are measured in TPI's - ties per inch.

The measure of an adhesive's ultimate holding power or bonding strength. A bond that makes label removal difficult or impossible without distorting or destroying the face material.

Permanent Adhesive
See: Adhesive: Permanent.

Phosphorescent Face Material
A face material coated with a phosphorescent ink. See: Phosphorescent Ink.

Phosphorescent Ink
An ink that absorbs and reflects light and remains luminescent after exposure to a light source has stopped. It is commercially called Glow-in-the-Dark.

This type of label consists of a pressure sensitive label on a pressure sensitive liner. This double-ply label is carried on a standard release liner. Once the double-ply is applied to a substrate, the top ply can be removed and applied to yet another substrate. Typically this kind of label is used for response labels in direct mail promotions.

A substance added to polymeric materials to impart flexibility, workability, and elongation.

Plasticizer Migration
The movement of plasticizers from a plastic into an adhesive or face material, or both. This can cause degradation of the adhesive and bleed-through of adhesive components into the face material.

A b film that is resistant to moisture, solvents, oils, and chemicals. It is usually transparent, but is available in White or with a metallized finish.

A tough, stretchy film that is suitable for use in low temperature applications. It is frequently used for labelling semi-rigid bottles.

Pressure Sensitive Label
A self-adhesive label that is the diecut, usable part of pressure sensitive material that has been converted through roll-fed production equipment. The end product can be produced in rolls, sheets, or fan-folded stacks.

Pressure Sensitive Material/Pressure Sensitive Stock
The combination of face material, pressure sensitive adhesive and release liner from which pressure sensitive labels are manufactured.

Price Mark Labels
Labels for retail and/or wholesale use that normally carry alpha or numeric character information such as: unit price, lot number, style number, and SKU number.

Prime Label/Primary Label
Usually a descriptive, decorative product label, the label typically on the front of a container.

Print Resolution
The quality of print; the level of detail achieved by a printer. Measured in dpi (dots per inch), typical capabilities are 200 dpi for a thermal transfer printer and 300 dpi for a laser printer. It is particularly critical in bar code printing.

Protective Coating
A coating that protects the printing and the surface of a pressure sensitive label for abrasion, sunlight, chemicals (their fumes and dilute solutions), and moisture, or a combination of these.