variable length code

a code whose number of encoded characters can be within a range, as opposed to a code with a fixed number of encoded characters.

vegetable gum

a class of adhesives derived from plants or plant material.

vellum finish

a full, toothy finish which is relatively absorbent for fast ink penetration. Text papers in books frequently have a vellum finish. Vellum would not be as smooth as a smooth offset or English Finish grade.

verifier

a device that makes measurements of the bars, spaces, quiet zones and optical characteristics of a symbol to determine if the symbol meets the requirements of a specification or standard.

vertical bar code

a bar code pattern presented in such orientation that the symbol from start to stop is perpendicular to the horizon. The individual bars are in an array appearing as rungs of a ladder.

Viscosimeter

an instrument for measuring the viscosity or resistance to flow of a liquid.

vinyl

synthetic plastic products manufactured in rigid or flexible constructions. also known as pvc. tough, durable film having excellent resistance to oils, chemicals and many solvents. it can also be colored.

viscosity

the tendency of liquids to flow. The main unit of measure is centipoise. See also centipoise.

VLD

visible laser diode.

void

In coatings, a bare uncoated area on a film. In bar codes the undesirable absence of ink in a bar.

wall thickness

the difference between the inside diameter or id and the outside diameter or OD of a tube or core. Thick walls would offer more strength than thin walls.

wand

see Wand Scanner.

wand scanner

a hand-held scanning device used as a contact bar code or OCR reader.

warp

a cloth term describing the lengthwise thread or yarn pattern running the length of the loom. Warp is usually stronger than the woof. Ease of tearing is greater with the warp and across the woof. Warp and woof thread count is specified on raw materials. The quantity of threads have a bearing on the strength of cloth. Holland, Cambric, Gusset and Clayfilled Splicing tapes are all cloth items. See also woof.

waste

see matrix. This can also refer to sub standard material that needs to be thrown out as a result of production process. A printer could complain, for example, that his waste levels were too high as a result of a defect in the material.

water sensitive

a water moistenable adhesive that activates when water is applied. There are two major types of water sensitive adhesives -- dry gum and conventional gum. Generally water sensitive adhesives only stick to paper and paper products. Some will adhere well to glass. See also dry gum and conventional gum.

water soluble adhesive

a pressure sensitive adhesive in which all components are water soluble. Sometimes this is referred to as a wash away adhesive.

waterproof

a relative term applied to papers which have been heavily treated or laminated to resist moisture. See moisture resistance.

wax pick

testing of pick properties of coated papers is frequently done with a wax pick test. Sticks of special wax are melted and applied to the paper. They are removed with cool. The result is reported as the highest number wax that does not disturb the surface of the paper. There are other test methods of determining pick levels.

weatherability

the capability of a pressure sensitive label to withstand the effects of weather.

web

a continuous sheet of pliable manufactured material, usually in roll form.

wedge

a device that plugs in between a keyboard and a terminal. It allows data to be entered either by keyboard or by various types of scanners.

weft

the threads that cross the warp in a woven fabric.

wet end

the beginning of the paper machine comprising the headbox, wire and press sections.

wet strength

the tensile strength of paper if it is wetted after manufacture. Wet strength is increased by adding certain synthetic resins to the furnish.

wetting

the relative ability of a liquid adhesive to flow uniformly over the substrate.

whiteness

the degree of approach of the color to that of the ideal white. High whiteness is associated with low purity and high visual efficiency. Hue, saturation and brightness of color have a bearing on apparent whiteness.

wicking

the tendency of a liquid to travel through paper.

wire

the moving screen at the wet end of a paper machine where the sheet is formed.

wire side

paper is made on a continuous horizontal wire called a Fourdrinier. The side of the paper that comes in contact with the wire takes on the impression of the pattern of the wire. The felt side would be the opposite side of the paper. The wire side is not as smooth as the felt side. Generally we coat adhesives on the wire side. This allows the print surface to be as smooth as possible.

woof

a cloth term describing the threads cross woven. Woof is not as strong as warp. Tearing is easier across the woof. See also warp.

wrap-around label

a label that extends completely around a container. Usually there is an overlap of label to label.