Updated 13 March 2010
Vacuum packaging – A package from which the air has been withdrawn before sealing.
Valence – A number representing the proportion in which a given atom or radical combines. This number usually represents the number of electrons involved in the shift of an element from one reaction state to another.
Validation – Documented procedure for obtaining, recording and interpreting the results required to establish that a process will consistently yield product complying with pre-determined specifications (ref. ISO 11607 – 2003(E)).
Value – A density or numeric assignment of a colour, tone or density made by direct comparison or by use of a densitometer. Colour printing values range from 2% minimum controllable dot to 98% maximum controllable dot. Values in colour can be pre-selected for density, hue and depth by using a process printing guide. This is ideal for pre-visualizing how a particular colour may be reproduced on a printing press.
Vapour Release Pouch –
Variability – Changing data on one or more impressions of a print job to enable some change in data depending on audience segment.
Varnish – (1.) A transparent liquid coating that is applied to a printed product to either protect it or make it visually more pleasing. Varnish is essentially ink without pigment. It requires its own printing unit on press. It can be wet-trapped (printed in-line at the same time other inks are laid down), or dry-trapped (run as an additional pass through the press after the initial ink coating has dried). The latter often provides a glossier finish. Varnish comes in gloss, dull, and satin (in-between dull and gloss), and can be tinted by adding pigment to the varnish. From an artistic standpoint, one can play a dull-varnished portion of the sheet against a portion without varnish or with a gloss varnish. This contrast can give emphasis to certain areas and/or give the impression of depth. (2.) The vehicle or “carrier” component of an ink, more commonly used in offset terminology.
Vat-Lined Board – Cylinder boards which have one or both of the surface linings composed of furnish different from the inner plies. They may be coloured.
VDP – variable data printing (technology)
Vector – A generic name for saving picture information. Vector files are saved by recording the positions of the points that define a shape filled with one colour. PostScript describes images as vector information, allowing you to translate Postscript into linework. These formats are also called “Resolution Independent” meaning that they can be redrawn at any size and still have clean edges.
Vehicle – One of the basic components of ink. Vehicles carry the colorant and keep it dispersed throughout the printing process. The vehicle is composed of binder and solvent.
Veining – Uneven colouring of pulp.
Vellum – A fairly even uncoated paper finish.
Verification – The process of checking that a product, service, or system meets specifications and that it fulfils its intended purpose. These are critical components of a quality management system. (http://en.wikipedia.org)
Verso – The left-hand page opposed to the recto. The verso always carries an even numbered folio. Also refers to the reverse side of the sheet.
Vertical Adjustment – Raising and lowering mechanism to position blade for size cylinder being used.
Vertical Reciprocating Press – Press in which both the form and impression cylinders move up and down in a reciprocating motion.
VFFS – vertical form fill and seal (machine).
Vickers – A hardness scale representing the degree of deformation of a material when subjected to a specific diamond stylus carrying a given load for a certain length of time.
Viewing Booth – A enclosed area with controlled lighting that is used in graphic arts studios, service bureaus, and printing companies as a stable environment for evaluating proofs and press sheets. Viewing booths are generally illuminated using graphic arts industry-standard D65 lighting, and are surfaced in neutral grey colours.
Vignette – (1.) A gradation change of only one colour that varies only in strength or lightness. (2.) An illustration or image that gradually fades away, blending into the unprinted paper. It is sometimes referred to a graduated background tone.
Vino-Seal closure (glass stopper) –
Vinyl – Polyvinyl chloride, another name for PVC. This strong clear material is used as the outer substrate on some coffee bags. It presents well, has excellent elongation and tear strength properties, and is used on coffee bags, where appearance is more important than price.
Virgin Material (Fibre) – Fibre gleaned from organic materials such as wood chips which has not been previously used in the manufacture of another product. Also primary fibre (cf. secondary fibre).
Viscometer – An instrument used to measure the viscosity of a liquid.
Viscose pulp – Dissolving pulp intended for the manufacture of viscose.
Viscosity – A fluid’s resistance to flow, varying with temperature, agitation or rate of flow.
Viscous products –
Visible Radiation – The range of electromagnetic radiation from 400-800nm.
Visible Spectrum – Light that is visible to the human eye and is perceived as different colours. The visible spectrum is the 400- to 700-nanometer portion of the electromagnetic spectrum, which is the entire range of wavelengths from gamma rays to the longest radio waves. Infrared wavelengths are longer, and ultraviolet wavelengths are shorter than the visible spectrum.
Vitro Packaging –
VMPET – Vacuum Metallised PET. This material consists of PET, which has been metallised with aluminium. It serves as a light and oxygen barrier, and is often used instead of aluminium. It has a slightly more smooth appearance than aluminium; however it is slightly less efficient as a light/oxygen barrier. It is however cheaper and more environmentally friendly.
VOC’s – see volatile organic chemicals or compounds.
VOC Emissions – VOC’s which are put into the air or emitted by various sources.
Volatile Air Compound (VAC) – An air compound that has the property to readily vaporize at a relatively low temperature.
Volatile corrosion inhibitor (VCI) paper – Paper specially designed to resist corrosive liquids.
Volatile Organic Compounds (VOCs) – Any organic compound which evaporates readily to the atmosphere, thereby contributing to photochemical smog production and certain health problems. Test Methods: Publication Rotogravure Inks and Coating – EPA Reference Test Method 24A, All other thin film Inks/Coatings – EPA Reference Test Method 24
Volatility – The ability of a material to readily vaporize at a relatively low temperature.
Volcano – Printing imperfection resembling the crater of a volcano, generally noticed in heavily inked areas; caused by solvent vapours having burst through and shattering the surface of the ink film.
Volt – The unit of electromotive force, or difference in potential, which will cause a current of one ampere to flow through a resistance of one ohm.
Voltage Efficiency – The ratio, usually expressed as a percentage, of the equilibrium reaction potential in a given electrochemical process to the bath voltage.
Voltmeter – Coulometer. A device used to measure voltages.
Volume – (1) The amount of water displaced by a model of a container; used to estimate its capacity. (2) The amount of product a container is designed to hold.
Volumetric Analysis – A method of analysis that depends upon measurement of the volume of standard solution consumed in a titration.
VPS – Virtual Packaging System.