Offset printing

A method of printing from a plane surface on which the image to be printed is ink receptive and thus carries the ink to the surface being printed, while the non-printing areas are ink repellent. The ink is transferred to the surface being printed by means of a flexible blanket or ink transfer roll — hence the description “offset”. See also: Letterset (dry offset).

Oleophilic

Oil receptive, ink accepting/receptive surface (of a printing plate, for example).

Oleophobic

Oil repellent, ink repellent surface.

One-way bottles (cans)

See: Non-returnable container.

Opacity

Resistance of a material to the transmission of light. The degree of non-transparency of a material.

Open-cell foamed plastic

A cellular plastic in which there is a predominance of interconnected cells.

Open mesh

A woven material with spaces or gaps between the fibres to permit the ventilation. Used for fresh vegetables such as onions, potatoes and fruits, etc.

Open time

The interval between the application of an adhesive to a surface and the subsequent activation of the adhesive or “set” bonding with another surface.

Optical character recognition (OCR)

A method of marking price tickets, credit cards and many other retail documents with a set of letters and numbers so they can be read universally by customers, retailers, ven­dors and others by eye, by wands or price ticket readers.

Orange peel

Uneven surface fault on moulded plastics, somewhat resem­bling orange peel.

Orientation

In the manufacture of plastic films, sheets or bottles, the material is stretched to align the majority of molecules in a particular direction. The stretching may be in the machine direction only — uniaxially oriented — or in both the machine and cross direction — biaxially oriented. If the material is subsequently heat-set, the orientation is effectively permanent, otherwise, it will attempt to return to its original relaxed condition when heated — e.g. shrink film.

Orifice Reducer

Plug or fitment with a controlled-diameter opening. When inserted in the inside diameter of a bottle neck finish, it reduces the flow of product being dispensed.

Outage

The amount of vacant space allowed in a drum or other container to accommodate the density variations in the commodity, or for ex­pansion due to temperature variations. In food containers, the outage is called headspace.

(2) The vertical distance from the top of the bottle finish to the surface of the liquid directly below the finish.

(3) Outage for dry granular products --The distance between the top of the package and the leveled product. Outage varies with the degree of product settling.

Outer package

An outer container usually made of steel, wood or fibreboard designed to enclose and protect one or more smaller and normally more fragile containers.

Out-of-Round

A container manufacturing defect,in which a round container is or becomes slightly oval.

Outsert

A folded printed sheet, leaflet, etc. bearing an advertising message or instructions, af­fixed to the outer surface of a container or package.

Ovenable paperboard package

A paperboard container, normally for processed foods which can be heated in a conventional or microwave oven. Typically solid bleached sulphate board. Can be extrusion coated with suitable heat-resistant plastics.

Overcap

A secondary closure that fits over the primary closure or sealing mechanism. It may protect the primary closure from tampering and/or accidental dispensing. Overcaps are also used to enhance the appearance of a package.

Overflow Capacity

The capacity of a container to the top of the finish or to the point of overflow.

Overpackaging

A condition where methods used to package an item exceed the requirements for adequate protection.

Overprint

The result of printing of one layer over another, such as a varnish printed over an ink film to protect it or make a gloss finish or coat; or one layer of ink printed over another one to form color combinations.

Overseal

A secondary closure to impedetampering with the primary closure. An example is a tear-off aluminum seal placed over the replaceable closure of a large metal contain­er or drum. Generally used for exports, and more a,d more within the context of consumer protection.

Overwrapping

The application of a wrapper (film, foil or paper) over a product, a carton or tray. A packaging operation which normally has to be mechanized to achieve good, consistent results.