Vv

VAC
acroynm for volts alternating current.

vacuum
(1) air evacuation system that creates suction between a substrate and the printing base to hold the substrate in position during printing; (2) air removal system to draw heat softened plastic sheets to mold or die for forming.

vacuum back
the top or back of a process camera that includes a suction device to hold photographic paper or film in place during exposure.

vacuum forming
a technique for thermal shaping a flat plastic sheet into a 3-D shape by heating the sheet until flexible and then withdrawing air from between the heated sheet and a mold or die.

vacuum frame
a suction device for holding copy and reproduction material in contact during exposure.

vacuum holes
the holes in a forming mold, printing base, or printing frame through which air is exhausted.

vacuum metallizing
a technique for depositing a very thin film of metal on a substrate to produce a metallic foil appearance on its surface.

vacuum table
a flat printing base with a series of holes drilled in its bed for use with an air evacuation system for holding down a substrate during printing.

valley printing
(1) printing concave parts; (2) printing within a depression or surface that is below the highest level of an object such as the inside of a bowl.

value
the relative lightness or darkness of a color measured against a neutral gray scale (ranges from 0 for pure black to 10 for pure white).

value scale
a complete range of values from black to white.

vapor
the gaseous state of any substance that under normal conditions is liquid or solid.

vapor density
(1) the weight of a vapor compared to air; (If less than 1.0 vapor rises, if greater than 1.0 vapor will settle to floor); (2) the relative density or weight of a material in its vapor state (with no air present) compared with an equal volume of air at ambient temperature.

vapor permeable
property of allowing a vapor to pass through a material.

vapor phase soldering
a soldering process that uses the latent heat of vaporization of a liquid as its energy source.

vapor pressure
the outward pressure of a mass of a given vapor at a specified temperature, used as an indicator of volatility, expressed in mm of Hg at 20 degrees C.

variable
a quantity or condition that tends to vary; having no fixed quantitative value.

variable-contrast paper
photographic paper that provides different grades of contrast when exposed through special filters.

variable type gauge
provides a quantitative value for the past characteristic being checked.

variance
a deviation from a job specification or standard.

varnish
(1) a medium in which pigment is ground to make an ink; (2) a thin transparent protective coating applied to a printed sheet for protection or appearance; (3) a material added to an ink to increase transparency.

varnishing
a process whereby a sheet is coated with a film forming liquid to give a smooth glossy finish.

varnish-on decal
an image designed to be applied to a surface by means of a coating of varnish applied just prior to placement.

vat dyes
synthetic organic dyes in paste or powder form.

VDA 6.1
Verband de Automobilindustric, a quality system requirement for suppliers to German automakers.

VDE
acroynm for Verband Deutacher Elektrotechniker in Germany.

vector
(1) a graphic drawing specified as a color; (2) a mathmatical description of an image and its placement.

vector file
an electronic file that describes geometric shapes and dimensions in terms of coordinates or other symbols.

vector graphics
drawing software.

vector image
a computer image that uses mathmatical descriptions of paths and fills to define the graphic.

vee lock
a display lock used in shaping light weight stock.

vegetable parchment
a grease and water resistant paper made by passing unsized paper through sulfuric acid to gelatinize the surface.

vehicle
the fluid portion of printing ink that acts as a carrier for the pigment and enables it to flow.

veiling
gold and organic colors applied to glass in a threadlike texture.

Velcro®
registered tradename for a brand of hook and loop fabric fasteners.

vellum
a fine parchment made from treated calf, lambskin, or kid skin used as a writing material; (2) a heavy off-white fine-quality paper resembling this parchment.

vellum finish
a toothy finish that is absorbent for fast ink penetration.

vellum glaze
a semi-matte glaze having a satin-like appearance.

veloc
abbreviation for velocity.

Velox®
Kodak tradename for high contrast photographic paper; a photographic print made from a halftone negative, or from a continuous tone negative through a halftone screen.

vent
a small opening placed in a mold to allow air to exit as the molding material enters.

ventilation
to circulate fresh air into an area to replace stale air.

verify
sample sew-out of a new embrodiery design to make sure the pattern is correct.

vermilion
a bright red mineral pigment composed of mercuric sulfide artifically made from a preparation of sulfur and mercury.

verso
the left hand side of a page, book, or cover; the even numbered pages.

vertical ager
refer to tower ager.

vertical camera
a camera where the film holder, lens, and other head components are positioned directly above the copy board.

VHAP
acroynm for volatile hazardous air pollutant.

vibrating colors
contrasting colors of the same value placed side by side causing an apparent vibration or jump between them.

vibrating parts feeder
a device that supplies small parts to a machine single file, all oriented the same way.

vibration flocking
the erection of applied flock fibers by passing the flocked substrate over a beater or vibrator bar.

victoria blue
a clean, red shade organic blue dye or pigment.

view camera (studio camera)
a camera with an adjustable back and the lens board, a film holder section that tilts vertically or horizontally, and a lens board that moves up, down, or to the side for distortion control. (A view camera can be used as a process or copy camera if both the lens and film plane are locked into a center and parallel position).

view file
a low resolution electronic file containg the actual data used to form the final output page.

viewing booth
an enclosed area with controlled lighting for evaluating color proofs and press sheets.

vignette
an image that fades off gradually into the background; a transition from one color or intensity to another.

vignetting
printing the central area of a picture while shading the edge areas gradually into white or black.

vinyl
the univalent chemical radical CH₂CH obtained from ethylene; a tough flexible synthetic thermoplastic; also referred to as polyvinylchloride.

vinyl ink
an ink designed for use on vinyl films, usually solvent-based.

virgin mesh
new screen mesh that has never been used for printing.

visc
abbreviation for viscous.

viscoelastic
characteristic mechanical behavior of some materials that is a combination of viscous and elastic behavior.

viscoelastic ordering
the alignment of stretched chains within a polymer along the axis of deformation, improves the strength of a film along the axis.

viscometer
an instrument for measuring the resistance of a liquid to shear or flow at specified temperature and atmospheric conditions, by measuring the force required to move one layer over another without turbulence; also referred to as viscosimeter.

viscosity
the degree of fluidity, tack, or internal resistance to flow, of a compound ranging between liquid and heavy paste.

viscosity coefficient
the constant of proportionality of the viscous force to the velocity gradient between two parallel Newtonian fluid layers.

visco-spatula
an instrument used with a timing device to measuring ink run-off from one marking to the next.

viscous
a material that is thick; resistant to flow.

visible light transmission
the ratio of the amount of total visible solar energy (370 to 780 namometers) that is allowed to pass through a filter, to the amount of total solar energy falling on the filter.

visible spectrum
the region of the electromagnetic spectrum between 380 and 720 nanometers.

vitreous enamel
an enamel that requires fusion at high temperature to form its characteristic hard glossy surface, sometimes referred to as a porcelain enamel.

vitrify
to change into glass by heating.

VM & P
a naphtha of high flash point solvent employed in the manufacture of some inks. (The initials refer to varnish maker’s and painter’s naphtha).

VOC.
acroynm for volatile organic compound.

void
(1) the failure of an ink to completely define a graphic feature; (2) an air bubble that has been entrapped in a plastic part during the molding process; (3) holes containing no matter in a fired film.

voids
holes in a coating film, refer to pinholes.

vol
abbreviation for volume.

volatile
subject to evaporation at a relatively low temperature.

volatile organic compound (VOC)
a liquid solvent that tends to vaporize at room temperature. (High concentrations can be injurious to health).

volatility
the ease that a liquid or solid passes into a vapor state.

volume resistivity
the electrical resistance between the opposite faces of a solid volume of insulating material, measured under perscribed conditions using a direct current potential after a specified time of electrification, expressed in ohm/cm; the ratio of the electrical resistance through a cross section divided by the length through which the current flows.

volume shrinkage
the amount of dimensional change during cure.

volumetric dilatancy
a flow characteristic of material that behaves like a solid rather than a fluid, typically having a high solids concentration.

Vth
abbreviation for theoretical ink volume.

vulcanization
in plastics, a chemical reaction where the physical properties of an elastomer are changed by causing it to react with sulfur or other cross-linking agent; (2) ceramics, the formation of a liquid phase that upon cooling becomes a glass bonding matrix.

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