Glossary

-- A --

Abrasion Resistance — The ability of a given surface to resist scratching or scuffing due to contact or friction with another material. It is one measure of durability.

Abrasive Method — Acid etching or sand blasting to alter the surface of a material. The material is masked & an abrasive method applied, incising a graphic into the substrate.

Acetate — A thin flexible plastic sheet. Durable & stretch resistant. Available in glossy & matte finishes, receptive to ink. Popular material for point-of-purchase advertising signs.

Achromatic — Without colour. Black, white & grays.

acid-etching — A method similar to sandblasting,used primarily for marking glass. A stencil of the artwork is either hand- or computer-cut and applied to the glass, which is then brushed with an acid mixture such as ammonium and sodium biflouride. After a specified length of time, the surface is washed and the stencil removed. Also called etching.

Acrylic — An extruded or cast rigid plastic characterised by its clarity and colour-ability.

Acrylic paint — Any water-based paint having its pigments or dyes bound in an acrylic resin emulsion. Once dry, acrylic paint forms a tough, flexible film that is resistant to water. These types of paints are often used for silkscreening and screen printing and for hand painted signs.

Adhesive — A material able to hold two surfaces together, often activated by heat or pressure.  

Age in — The initial time a new neon light must be on before it is able to achieve full brightness thereafter. The amount of time this takes can vary widely. (Also called burn-in. See also initial lumens.)

Airbrush — A handheld painting device that uses compressed air to generate a fine spray of paint. The pressurised air passes through the airbrush nozzle creating a vacuum that siphons paint from an attached container. Airbrushes come in a variety of sizes for different applications, and can be fitted with a variety of nozzles for different effects and levels of detail.

Aluminum — A lightweight metal material used in sign panels, poles and frames. It is strong and durable in relation to its weight, and resistant to rust and corrosion.

Ambient light — The sum of all non-directional light in a given area emitted by all sources at a given time. A high level of ambient light can have an impact on a sign's readability, and can be a consideration in a sign's design. Outdoor sunlight creates a high level of ambient light.

Anchor — In sign making, refers particularly to the fasteners used to secure awnings and fascia signs to facades.  

Animated sign — A sign that shows motion or changes in copy or colour by means of an electric or electronic switching device. See flasher.  

Anneal — To subject to great heat, and then cool slowly. Neon tubes are annealed after bending to reduce stress in the glass.  

Anodising — Process by which a protective aluminum oxide layer is applied to an underlying metal using electrolysis.  

Anti-aliasing — In digital printing, the process of mixing various amounts of surrounding colours to pixels (or dots) forming lines or edges of colours. Helps eliminate the jagged look that sometimes occurs.  

application: The installation of vinyl on a surface. Two main methods are used:wet and dry. Wet application involves the use of a soapy solution or special fluid on a surface, allowing the vinyl and its transfer-tape carrier to be positioned before final placement. Dry application places the vinyl and transfer tape immediately in its final position, and usually involves hinging for setting the material.

applique: A graphic element made separately then affixed to a cloth or fabric covering such as an awning.

Application tape — See transfer tape.  

Aqueous Inks — Inks that use water as a carrier.  

architectural signage: A term used to describe signage in a built environment having the purpose of providing wayfinding or other site specific information.

Argon — An inert gas which, when mixed with mercury, is used in fluorescent lamps and neon tubes.  

Awning — A shelter constructed of non-rigid materials on a supporting framework which projects from and is supported by the exterior wall of a building. An awning may or may not be illuminated and/or decorated with graphics to serve as a sign.

-- B --

Back-lit sign — A sign consisting of a cabinet containing a light source surrounded by one or more translucent faces, illuminated for visibility.

Back-to-back sign — A sign having two faces mounted in opposite directions. Pole signs typically have back-to-back faces. (Also called a double-faced sign.)

Backlighted letter — An illuminated reverse channel letter where the light from the letter is directed against and reflected off the surface behind the letter thereby producing a glowing effect around the letter. (Also referred to as halo lighting.)

Baked enamel — A type of metal sign finish. A special enamel paint is sprayed or screen printed on the metal surface, dried, then cured. The result is an extremely durable surface similar to that found on many appliances.

Ballast — A device that operates as part of a fluorescent lamp and is designed primarily to provide sufficient starting voltage.

Banding — The appearance of solid bands or patterns of visibly distinct colours within what should otherwise be a continuous and seamless colour gradation. Banding can be caused by several factors, including low resolution artwork, a poor quality scan of the original artwork or improper calibration of the printer used.

Banner Pennant— A sign  usually made of fabric, vinyl or other non-rigid material with no enclosing framework. May be painted, screen-printed, digitally printed or decorated with vinyl.

Bevel — 1. A slant or angle on a surface. 2. A cut made at the edge of a material to form an angle that is not 90¡. 3. Two adjoining surfaces that do not meet at right angles are said to be beveled

Bitmapped — Describing when arranged pixels comprising a graphic or an image become visible/detectible by the human eye. When incompatible image file formats are imported, often the graphic will appear bitmapped with squared-off pixels resulting in jagged edge effect on perimeter of line art or loss of resolution on images.

Binder — A substance that binds two others together. For instance, lacquer is used as a binder when painting with some metallic dusts, and many paints require binders.

Blackout —A specially formulated paint or coating for use on electric signs to block light emission where needed, for example between letters in a neon sign. It adheres well to glass, and resists weather, heat and electrical discharge. (Also called blockout.)

Blade sign: A type of projecting sign mounted such that the face of the sign is perpendicular to the normal flow of traffic.

Blank — Most commonly, an undecorated face. May also refer to a sign face without any framing or cabinet.

Blistering — The appearance of bumps and bubbles on a surface covered in a coating such as paint, or a material such as vinyl. It is the result of the coating or material losing adhesion and separating from the surface underneath.

Blockout — Specially formulated paint used to block out the crossover connections (light) between neon letters.

Bombarding — The process of heating the glass and metal portions of a neon tube to a high temperature to release all absorbed gases and other impurities.

Bulletin colours — Specially prepared enamel paints preferred by many sign painters for hand-lettering.

Burning-In — Recommended to bring a neon tube to its proper brilliance, burning-in involves connecting the completed tube to a transformer similar to that which will be used in the installation and allowing it to remain lighted until proper brightness, colour and electrical properties are achieved. Also called aging.

Burnish — To polish by rubbing, a common practice in the gilding process.

Back-lit sign — A sign consisting of a cabinet containing a light source surrounded by one or more translucent faces, illuminated for visibility.

Baked enamel — A type of metal sign finish. A special enamel paint is sprayed or screen printed on the metal surface, dried, then cured. The result is an extremely durable surface similar to that found on many appliances.

Ballast — A device that operates as part of a fluorescent lamp and is designed primarily to provide sufficient starting voltage.

Banner Sign — usually made of fabric, vinyl or other non-rigid material with no enclosing framework. May be painted, screen printed, digitally printed or decorated with vinyl.

Binder — A substance that binds two others together. For instance, lacquer is used as a binder when painting with some metallic dusts, and many paints require binders.

Blank — Most commonly, an undecorated face. May also refer to a sign face without any framing or cabinet.

Blockout — Specially formulated paint used to block out the crossover connections between< neon letters.

Bombarding — The process of heating the glass and metal portions of a neon tube to a high temperature to release all absorbed gases and other impurities.

Bounding box — The area of an on-screen image at its maximum x- and y-axis measurements. Altering the bounding box by moving its control points can change the shape or size of an image. Bounding boxes allow scaling of all graphics images in PostScript file types.

Box sign — A sign that is self enclosed in a typically square or rectangular structure with or without internal lighting. Can be single- or double-faced. (See also light box.)

Branding — The process of creating a unique, positive and recognisable identity for a product or service. Along with marketing and advertising, creating a visual identity through signage is an important part of the branding process.

Brushed finish — A textured, non-reflective polished finish applied to metal by lightly brushing the surface with an abrasive material or briefly applying a mildly corrosive chemical.

Bulletin colours — Specially prepared enamel paints preferred by many sign painters for hand-lettering.

Built-up letter — A lettering technique in which the outline of the letter is made first and then filled in.

Bulletin colours — A type of quick drying, fade resistant enamel paint commonly used by sign painters for hand lettering.

Burning-In — Recommended to bring a neon tube to its proper brilliance, burning-in involves connecting the completed tube to a transformer similar to that which will be used in the installation and allowing it to remain lighted until proper brightness, colour and electrical properties are achieved. Also called aging.

Burnish — To polish by rubbing, a common practice in the gilding process.

Bushing — In a neon sign, insulates the electrode from a metal sign. Requires a separate connection between the electrode and the high-voltage line.

-- C --

Cabinet — An electric sign, not including the components and structure. A cabinet is made up of a face and back, or two faces, along with the edge. (Also called can)

Calendered — Vinyl sheeting squeezed between a series of heated rollers (also extruded) to achieve a small-enough thickness for cutting with a knife plotter. Calendered film is generally thicker and less expensive than cast vinyl.  

Calibration — Operation of matching colour shades and hues between input (design software/ monitor/scanner) and output device (printer). Also the operation of keeping colours consistent during printer operations, compensating for changes in humidity, media, toners, etc.

Can — An informal term for the edge and components of an electric sign. Some sign companies buy readymade cans and only manufacture the faces of electric signs. Also called sign cabinet.

Candela — A unit of luminosity used to express the intensity of a light source as measured in a specific direction. The higher the number of candela measured, the greater the intensity of the light.

Carved letters — Lettering that is chiseled, routed, engraved or sandblasted into the substrate of a sign face either by hand or by computer controlled machinery.

Carrier — Substance in which pigments in inks are suspended. Aqueous, solvent and eco-solvent carriers evaporate after printing. Monomers are considered carriers in UV-curing inks, but are transformed into solid polymers after curing.

cast acrylic — A type of plastic sheeting formed by spreading a molten vinyl mixture on a carrier sheet or web, and then baking at high temperatures to remove solvents and to fuse the remaining material into a film.

Cast — Vinyl sheeting formed by spreading a molten mixture on a carrier sheet, and then baking at high temperatures to remove solvents and fuse the remaining material into a film. Cast film is usually thinner and more-expensive than calendered vinyl.

Casting — The process by which a material such as metal or plastic is poured into a mold while in a liquid state and then allowed to solidify, thereby taking the shape of the mold and creating a copy of the original object from which the mold was made. (See also die-casting.)

Changeable copy sign — A sign where the copy on the face can be changed at will either manually using attachable letters, mechanically using a rotating panel or electronically via computer-controlled bulbs, LEDs or LCD screen, etc.

Channel letter — The outline of a letter, with extended sidewalls that create depth, into which a light source is placed.

Chase — 1. The illusion of movement in neon tubes or incandescent bulbs created by turning the light sources on and off in sequence. 2. To decorate metal, typically by engraving or cutting.

CMYK — Cyan, Magenta, Yellow and Black, or the four process colours. Used in screen printing and by output devices such as inkjets, electrostatics, and thermal-transfer printers.

Coat-out — Painting the substrate of a sign with a coat of primer prior to applying the lettering and graphics.

Cold cathode — The technical name for all forms of neon lighting. The term cold cathode is< used to refer to 18mm to 25mm tubing operating at currents 60mA to 240mA. These gas discharge lamps also have electrodes that depend on a large emission surface area rather than high temperature for their operation.

colour management — Refers to coordination of colour with output and display. In output, colour management is often handled on a device-by-device basis by imaging production software (see RIP).

colour separation — The process of decomposing and separating a colour graphic or image into its four constituent CMYK ink colours such that each colour ends up with its own printing plate. The plates are then used in a printing press to reproduce the image on paper.

colour specification — colour values used to numerically specify a colour within a colour system.

Contrast — 1. The amount of difference between the lightest and darkest areas in an image or scene. 2. The visual characteristics of an object such as size, shape and colour that make it distinguishable from other objects near it and the background it is set against.

Conduit — A metal or PVC plastic tube for protecting electric cables.

Corian — A material produced from marble dust.

Corona treatment — A treatment process that alters the static charge of material's surface, making it more receptive to the application of inks, coatings and adhesives.

Corrugated board — A board created by gluing a corrugated piece to a flat face, or between two flat faces.

Coverage — The area (usually given in square feet) that a given material will coat-out.  

Craze — Thin cracks or breaks in paint, plastic or vinyl, caused mainly by weathering, though it may also be caused by the incompatibility of paint layers or solvents.

Crossover — The connection between two portions of a neon tube, intended to be unnoticed in the finished sign. Typically, crossovers are coated with blockout paint

Curing — The process of effecting a chemical change in some inks or paints by the application of heat or ultraviolet light.

-- D --

Debossed lettering — Sign lettering where the lettering has been engraved, carved or otherwise recessed into the sign substrate

Decals — Copy and/or graphics printed on the non-adhesive side of film, then cut to a specified shape.

Delamination — The separation of layers in a laminated substrate. Delamination is most often caused when edges are overexposed to moisture, temperature extremes or UV light, resulting in adhesive failure.

deposit — In sign making, this refers to the amount of ink applied to the substrate

Die-casting — The process by which molten metal is poured into a hardened metal mold and then allowed to cool and solidify, thereby taking the shape of the mold and creating a precise copy of the original object from which the mold was made or designed.

Density — In sign making, a measurement used to express the hardness of foam boards in pounds-per-cubic-foot.

Die-cut — A cut made with a steel rule die manufactured to cut a particular shape, commonly, when a large number of shapes with curved lines are to be cut. Also refers to the object that has been cut.

Diffusion pump — A vacuum pump consisting of a boiler, a jet assembly and a cooling chamber, designed to increase the speed of evacuation of a neon tube after bombarding.

Digital colour signage — Computerised output (usually sheet materials) that can be applied to fabric, vinyl,paper,high-pressure laminates, fiberglass embedment, and other material.

Direct Current (DC) — One of three varieties of electricity. Specifically, a current that always flows in one direction, around and around, as in the electricity that powers household batteries. See also Alternating Current.

Directional sign — Signs designed to provide direction to travelers. The Highway Beautification Act sets guidelines for the size, placement and content of true directional signs.

Directly illuminated — A sign that is illuminated by a source other than ambient light; any lighted sign.

Directory sign — An on-premise sign that identifies the names and locations of tenants in a multi-tenant building, or group of buildings.

Dot gain — Occurrence of dots printing larger than intended. The result may be bigger prints or darker colours, but also may create larger colour blocks and more defined images.

Dots-per-inch (DPI) — A unit of measure used to describe the resolution capability of a given piece of equipment by measuring the number of individual dots the device can reproduce in a linear inch. If the horizontal and vertical resolutions are different, typically both figures will be given. The higher the number of dots, the less easy it is to distinguish individual dots, making the image sharper.

Double tube — Two neon tubes running parallel to each other, often used for outlining or borders.

Double face — A sign with two parallel but opposing faces.

Double back — A 180-degree bend used in neon tubes to produce such letters as R, E, F and G. Often used to describe the technique and placement of the electrode on a neon unit.

Driver — power supply for LED systems, providing low voltage output.

Dye — A colourant that is dissolved in a liquid and applied to a surface or texture to change appearance.

-- E --

Eco-Solvent Inks — Inks using a less-toxic solvent-based carrier. Printers using eco-solvent inks emit less harmful VOCs (volatile organic compounds).

Electrode — A terminal that conducts an electrical current between two conducting substances. Electrodes are found at both ends of a neon unit.

Electronic Message Center (EMC) — A sign that utilises computer-generated messages or some other electronic means of changing copy. These signs include displays using incandescent lamps, LEDs, LCDs or a flipper matrix. Also called changeable message signs (CMS).

Electrostatic film — Vinyl film treated with a small charge of electricity, enabling it to temporarily, but firmly, adhere to glass and similar smooth substrates.

Emboss — The process of producing raised letters, particularly those produced by engraving dies or plates.

Emulsion —A semi liquid material that dries hard and is used in preparing stencils for screen-printing.

Enamel — A coloured, powdered glass-based compound that is fused to the surface of metal or glass for decoration and protection. An enamel finish is typically opaque.

Engraving — Method of marking metal, plastic or glass in shallow, negative relief utilising a bit or graver. Engraving may be done freehand, using a pantograph or computer-driven equipment.

Epoxy — A very strong, two-part adhesive--resin plus hardening agent--capable of bonding together a wide range of materials, including woods, composites and metals.

Etched and paint-filled — Etched (chemically) or incised (mechanically or by the abrasive method) and then filled with colour to create a desired contrast and appearance.

Exterior illumination — Illumination that is provided from a source separate from the sign itself, such as a spotlight. Also called indirectly illuminated.

Extrusion — A part created by forcing a raw material (usually metal or plastic) through a die to create a specific shape.

-- F --

Face — The decorated surface of a sign; the area on which the copy and art is placed.

Flasher — A mechanical device designed to interrupt the electrical current in a sign at regular intervals, turning the light source on and off to create a flashing image.

Flat —brush made with medium-length ox hair bristles, called a flat because the bristles are cut flat and tend to remain that way when pressed to its full width; useful in maintaining even stroke widths; 2. Refers to substrates, particularly metal and plastic sheets, as they are received from the supplier; an undecorated substrate; 3. Describes a finish that is duller than matte, and has little reflective quality.

Flexible-face material— Translucent material, usually decorated and then stretched across a frame to form awnings, billboards and other types of signage.

Flexible metallic tubing — A flexible conduit tube used to protect electric wiring.

Fluorescent lamp or tube — A type of lamp in which the light is produced by the fluorescence of a phosphor coating in the tube. In a fluorescent lamp, the tube is coated with phosphors and then filled with a mix of argon gas and mercury. When electrical current passes between the electrodes, the gas mixture emits ultraviolet (UV) light. The UV light is absorbed by the phosphors, which then radiate the energy as visible light.

Foam board — A type of lightweight, rigid board used for interior signs. Foam boards consist of a foam center sheet laminated on one or both sides by a variety of substrates.

Foam tape — Typically double-sided adhesive tape used for mounting sign plaques, letters,or other sign materials to vertical surfaces. Comes in black or white and in various thicknesses (1/32" to 1/8"thick) and widths (1/2" to 1" wide).

Footing — The (usually) concrete supporting base of a structure, as for a pylon or monument sign. Also called footer.

Formed — Refers to a plastic face or letter that has been heated and shaped to give it dimension.

Friction feed — Process where material is fed through a printer or plotter by placing it between a motor-driven grit wheel and two tensioned pinch rollers.

Frisket — An adhesive masking of paper or plastic used for (stencil-like methods of ) painting, sandblasting, silkscreening, and other processes. Friskets may be hand-cut or digitally cut.

-- G --

Galvanised — Steel or iron that has been protected by a zinc coating.

Gauge — A method for measuring the thickness of sheet metal. In the sign industry, most sheet metal ranges from 10-26 gauge.

Gilding — Considered by many to be the highest form of sign art, gilding is the application of thin metal sheets to glass,signs, and vehicles. After the work surface is clean and the design is marked out, a gelatin sizing is brushed on the area to be gilded. The gold leaf is lightly applied to the work site using a gilder's tip and static electricity. After the entire area is dry, the gold leaf is burnished and holes and imperfections in the gild are filled. The final step, if the gild is reversed on a window, is painting the backs of the letters (and an outline) or outlining them is it is a direct gild. On outdoor application, a protective clear coat is sometimes applied when the gilding is on incised stone.

Glaze — A ceramic coating matured to a glassy state on a formed ceramic article such as tile. This is achieved through application of intense heat in a kiln. The term also refers to the material or mixture from which the coating is derived.

Gloss — An indicator of the amount of light reflected by the finish of a surface. A high gloss finish reflects 80-90% of the light directed at it. Semi gloss 50-75%. Satin 30-45%. Matte finish 5-15%.

Gold leaf — Gold manufactured into thin leaves, commonly available in a range of from 10-23 karats.

Gradation — The smooth transition from one colour to another colour, from black to white, or from colour to the absence of colour. (Also called gradient.)

Grommet — A reinforced metal eyelet found in banners used to receive cords or other fasteners.

GTO — A type of insulated wire capable of handling high voltages on the secondary circuit of a neon sign.

-- H --

HDPE (High-Density Polyethylene) — A strong, relatively opaque form of polyethylene having a dense structure.

HDU (High-Density Urethane) — A type of hard foam product used in sign production. Urethane has the density and fabrication characteristics of wood, but only one-third of the weight.

Heat-activated — A type of adhesive that isn't sticky at room temperature but undergoes a chemical transformation when heated.

Heat bending — The process of heating PVC boards and then bending them to desired shapes.

Heat colour-transfer — A process of applying colour to fabric whereby a pigmented resin is activated by heat and then pulled into the fabric with a vacuum applicator.

Hexachrome — colour matching system created by Pantone Inc. for combining six colours to create a larger gamut of reproducible colour.

High-pressure laminates — Papers impregnated with thermosetting melamine and phenolic resins bonded at high temperatures (some well-known brands are Formica, WilsonArt, and Nevamar, for example) which are available in sheet sizes up to 48" x 144" x 1/16" and come in dozens of standard colours and patterns. Now available with custom digital artwork embedment suitable for outdoor use as well.

Hinging — Vinyl installation process where a cut vinyl image, the carrier liner and the transfer tape are placed on the target surface; a piece of masking tape is then attached to the top edge of the transfer tape. The liner is then slowly rolled off from the top edge, and the transfer tape and vinyl image are slowly smoothed onto the surface.

Housing — For neon tubing, made from porcelain or Pyrex glass, a housing mounted in the sign that provides the contact between the electrode and the lead-in wire.

-- I --

Inkjet printer — Device that drops liquid ink onto a substrate for printing. The thermal bubble type of inkjet heats ink to approximately 400 degrees F inside a small chamber before shooting it through a series of nozzles. A piezo-based inkjet puts ink in a small chamber and then sends a charge to contract piezoelectric crystal lining the chamber and send the ink through the nozzles.

Ink-receptive — Describes a substrate that can be made wet by ink when printed and that will bond with the ink after drying or curing.

Internally illuminated — A sign which is lighted through the use of internal electric fixtures or lampbanks. See backlit sign and exterior illumination.

-- J --

JPEG (Joint Photographic Exports Group) — A common file format for colour digital images. The JPEG standard utilises a 'lossy' data compression method, meaning that in order to reduce the overall size of the file a small amount of sharpness from the original image is sacrificed.

-- K --

Knife bevel — Angle of the vertical cutting edge of a plotter blade. Bevels can be between 30 degrees for general vinyl, and 60 degrees for sandblast mask.

-- L --

Laminate — A process by which different materials are layered and then bonded together using adhesion. The end result may be the creation of a substrate — such as medium-density overlay (MDO) — or the protection of the underlying surface, as when a clear, plastic film is laminated to a decorated surface.

Leading —Typographic term from the long-gone days of cold lead typesetting, where thin lines of lead were placed between lines for to provide spacing within a paragraph. In contemporary nomenclature, leading refers to LINE SPACING.

LED (light-emitting diode)— A semiconductor diode that emits light when voltage is applied; a solid state lighting component, used in signage for EMCs, channel letter illumination, edge lighting glass or acrylic panels or for various decorative lighting effects. Lead-in wire — The wire that connects an electrode to the power source.

Light box— A sign that is self enclosed in a typically square or rectangular structure and houses an internal light system for illumination of the sign face.

Lumen — A unit of measurement for light.

Luminous tube — Also, a neon or fluorescent tube, consisting of a sealed glass vacuum tube with an electrode at each end containing a specific gas. As an electrical current is passed between the electrodes, the gas is ionised and emits light.

-- M --

Magnesium plate (mag plate) — Composite metal sign material which can be acid-etched with fine detail for use in interior and exterior signs. Good for exterior-grade A.D.A. signs and more durable than photopolymer. Lighter weight and less expensive alternative to cast bronze or aluminum plaques. Because it is somewhat porous, it should be primed and painted rather than used as raw metal finish.

Magnetic sheeting — Magnetised strip laminated to a flexible plastic sheet and sold in rolls.

Masking — In painting or screen printing, the process of covering — usually with tape or paper — areas to protect them from receiving subsequent layers of paint or ink.

Medium-density overlay (MDO) — An exterior-grade plywood with an average veneer on both sides.

Mercury — A heavy, silverwhite metallic element liquid at room temperature. In neon tube processing, it may be mixed with rare gases, typically argon, to produce ultraviolet light.

Metal finishes — Sign finishes vary greatly between silver metals and yellow metals. Typically both include polished, brushed, satin, matte, painted, anodised, antique, oxidised, galvanised, chrome-plated, nickel-plated, engine-turned, and many others. Metals typically come in a mill finish (as fabricated by the manufacturer). There are many levels of finishes that relate to gloss and reflectance including matte, satin, non directional, abraded, brushed,and mirror finish.

Monument sign — A freestanding sign sitting directly on the ground or mounted on a low base.

MSDS — Material safety data sheet, provided by the manufacturer

Muntz metal — An alloy of copper (55 to 61 percent) and zinc (39 to 45 percent) with up to 1 percent lead. This brass is highly malleable and is used for sign plaques and letters.

-- N --

National Electric Code (NEC) — Electrical safety code adopted by many jurisdictions around the United States, published by the National Fire Protection Association.

Neon — A rare inert gas which, when an electric current is discharged through it, produces a reddish-orange glow. The word neon is also often used synonymously to describe a type of luminous tube sign, which may contain other inert gases such as argon.

Nesting — Placement of images or jobs in an arrangement to minimise waste of material when cutting.

-- O --

Off-contact — A way of screen-printing in which the screen is raised at least 1/8" above the substrate. It is the preferred method for printing nonabsorbent substrates.

Opacity— Measurement of resistance to light passing  through a particular substrate.

Opaque — Not clear or translucent; not allowing light to show through.

Outgas — The characteristic of a solid or liquid to vaporise under heat. Occurs in some plastics and paints if they are not through drying resulting in adhesive failure to anything applied over them. Also describes the release of impurities in vacuum systems such as neon tubes during processing.

-- P --

Pantone® Matching System (PMS) — Standardised series of thousands of colours, each with specific colour formulations and identification number.

Perforating wheel— A toothed wheel on a handle that allows it to rotate freely, used to trace line art, creating perforations for pattern making. Also called a pounce wheel. See pounce pattern.

Phosphors — Chemical powders used to coat fluorescent tubes. A range of phosphors is available to produce a large variety of colours and whites.

Photopolymer — A type of plastic having a photosensitive coating which can be masked and photo-etched to create a tactile sign message. It is commonly used for ADA signage that requires Braille lettering.

Piezo inkjet — A printing process that uses the oscillations of electrically-stimulated piezoelectric crystals to force ink through inkjet nozzles.

Pigment — A compound used to colour other materials, such as paints and inks. Pigments are insoluble, finely ground particles and may be organic or inorganic.

Pixelisation — Process where the number of pixels are simply multiplied to increase resolution. The result is a higher dpi but the altering of detail from smooth to square-step lines, or jaggies.

Plexiglas —The trade name for a brand of acrylic sheeting, which (like Kleenex) is often mistakenly used as a generic term.

Plotter — Device that interprets information sent from a computer and moves a tool head to a series of coordinates based on the device's X and Y axes. Sign makers use a plotter equipped with a knife to cut vinyl, with the X and Y coordinates forming an outline that can be weeded and installed on a surface.

Point-of-purchase advertising (P.O.P.) — In-store advertising designed to sell more and different products to shoppers once they are in the store. The term applies to a store's internal sign system, as well as special displays. Also known as point-ofsale advertising.

Polycarbonate — A specific thermosetting resin characterised by its durability, flexibility, machinery, and endurance under UV exposure. Lexan is a polycarbonate. See also acrylic.

Polymer — Stable chemical compound or mixture of compounds consisting essentially of repeated structural units. UV-curing inks, once cured, become a solid polymer.

Polypropylene — A type of plastic sheet used in banners, noted for its flexibility at low temperatures and its resistance to chemicals.

Polyurethane — A type of hard thermoset plastic foam used in sign production. It has the density and characteristics of wood, but only one-third of the weight. It can be used for carving and sandblasting signs much like wood.

Polyvinyl chloride (PVC) — a specific thermoset plastic which is weather and chemical resistant, available extruded into many forms or cast as sheets in a variety of colours and thicknesses.

Porcelain sign — A traditional process to coat metal with a ceramic slip which is fired at extremely high heat to create a durable, glasslike surface that is impervious to the environment.

Pounce pattern —A full-sized pattern of any design to be painted. Once the pattern is created, the outline is perforated using a manual or computer-driven perforation wheel. The pattern is then held firmly against the substrate and the perforations patted with powder, charcoal, or coloured chalk dust, leaving an outline of the design. This ancient technique was used by Michaelangelo to transfer images to the ceiling of the Sistine Chapel and is still in use today.

Powder coating — A specific process for applying paint to a surface that creates a very durable protective surface.

Prime — To coat a raw substrate prior to the application of paint or adhesive. A primer coat prevents subsequent coats of paint or adhesive from being absorbed.

Print strole — A pass of the squeegee across the screen in screen-printing. This forces the ink through the stencil onto the substrate.

Process colour — The three primary colours of printing — cyan (blue); magenta (red); and yellow; plus black. When printed as halftones in that order, they create a full range of natural colours. Their printing is also known as four-colour process or CMYK.

-- Q --

Quadratone — A printing process that uses varying concentrations of black ink instead of different colours such as CMYK (four-colour process). The result is heightened midtone and shadow appearance in black and white images.

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Rain lap —A method for applying printed paper or vinyl sheets by starting at the bottom of the area to be covered and working upward. As each strip is applied, it overlaps the one below it, preventing rain form getting into the seam and weakening the bond with the substrate.

Raster image — An image created by a collection of pixels arranged in a rectangular way.

Rasterisation — The process of translating data into a bitmap pattern for output by a digital printing device.

Reflective sheeting — Film with very small glass or glass-like materials encapsulated below its surface, creating the ability to bounce light beams back to its source.

Relief — The projection of art from a flat surface. The shortened form of " bas-relief."

Resin transfer — Method of heating a colour on a carrier sheet (called a ribbon or foil) and printing it onto a substrate. The plastic- based resin is fused onto a material such as vinyl, creating a more-permanent image with waterfastness and UV protection.

Resolution — In digital imaging and printing, the number of pixels (or dots) of information per horizontal inch of actual image; the higher the number, as measured pixels horizontally and vertically, the more-precise the pictured image. In plotting, the degree of accuracy that a plotter will place a knife-head in relation to a theoretical, perfect location of a coordinate.

Retainer — The slotted portion of the edge that holds the translucent face within a sign cabinet. The projecting rim around the sign face that holds it in place.

Reverse channel letter — Channel letter which has a face and sides but no back, and is pegged out from a background surface. When the inside of the channel is lit, it produced a halo effect around the letter.

Routing — Elimination of material in a substrate, using a tool bit that has been machined for this purpose. In computerised signmaking, using a CAD/CAM machine, a tool is programmed to eliminate material along a tool path created along x-,y-,and z-axes.

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Sandblasting— A pressurised stream of sand or synthetic particles used to remove material from a substrate, such as glass, wood or HDU. A rubberised stencil of the artwork is either hand- or computer- cut and applied to the substrate, which is then sandblasted.

Scoring — Cutting or notching a material prior to bending it. Sufficient scoring of some substrates-glass and some thick nesses of PVC boards, for example- will also allow them to be broken cleanly without cutting them all the way through.

Second-surface — Refers to a sign made of a clear substrate, such as acrylic, where the art is applied in reverse on what can be an interior face of the sign, providing extra protection from the environment. Some large exterior signs are painted that way,as are many smaller identification, way finding,restroom,and evacuation signs that are subject to handling on a regular basis.

Show card — An interior sign utilising a card stock substrate and often decorated with tempera paints. The standard show card size is 28" x 44".

Sign — Any device, structure, display or placard which is affixed to, placed on or in proximity to, or displayed from within a building to attract the attention of the public for the purposes of advertising, identifying or communicating information about goods and services.

Sign Foam — A brand of specialised polymer foam cell products designed for three-dimensional sign age applications, available in different densities and strengths. This open cell foam machines easily and holds shape well. When primed and painted, it can look like other more permanent materials.

Silk screening — One of the oldest and simplest forms of printing. A print is made using a squeegee to force ink through stencil or emulsion that is supported by fabric that has been stretched over a frame to create a screen. Several synthetic fabrics have replaced silk as the fabric of choice for screen printers. (See also screen printing.)

Single-face — A sign consisting of one face, rather than back-to back faces.

Sizing — The substance applied to the substrate before gilding in order to make the gold leaf adhere to the surface.

Solvent Inks — Inks that use solvent as a carrier. Commonly used for printing onto vinyl, and offering good outdoor durability. Printers using solvent-based inks emit VOCs and should be ventilated.

Spectrophotometer — Measuring device that takes the colorimetric and spectral values of samples from a printed piece or device and compares them to standard colours.

Spot colours — colour used for a specific need within a print. It may be a separate, special tone to match a corporate colour, or it may result from the overlapping of colours within a halftone.

Spun glass — A strong, lightweight material created from tiny glass threads woven into a fabric and then hardened using a special polyester resin. Fiberglass can be used to create sign faces and cabinets of varying sizes and shapes. (See also fiberglass.)

Stippling — A method for taking out brush marks and creating a transparent look on windows. Paint is mixed with linseed oil to slow the drying process, then brushed on the surface to be stippled. A stippler is created by wrapping a piece of cheesecloth or other lint-free cotton rag around a wad of cotton, which is then either held firmly in the hand or securely attached to a short stick,taking care that the work surface of the stippler is wrinkle-free. Stippling is done by daubing the stippler over the wet,painted surface.

Stochastic screening — A silkscreening process that conveys the tone of a screened image by varying the number and location of dots rather than just varying the size of the dots within the grid.

Substrate — The material out of which a sign face is made. Wood, metal sheeting, paper and acrylic are all sign substrates.

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Tagged image file format (TIFF) — Standard graphics file format used for scanned bit-mapped images.

Tangential knife — On a plotter, a blade holder that is mechanically turned to aid in deflecting the edge to create curved cuts.

Tempera — Pigment mixed in a water medium, usually with a binder and adhesive. Tempera paints produce a luminous effect.

Thermal-transfer printer— Device that uses a heating-element head to transfer resin- or wax based colours from a carrier sheet (a ribbon or foil) to a medium.

Thermoforming — Taking a flat sheet of material and giving it dimension by heating and then forcing it into a mold either mechanically or pneumatically. Also know as pan-forming.

Thinner — Any liquid used to reduce the thickness of paint or ink.

Three-dimensional (3D) engraving — A routing procedure where the tool bit can be moved independently along the up-and-down z-axis while still traveling an x/y-axis tool path. 3D engraving can create relieves and hand-chiseled looks while removing material from a substrate.

Throughput — The actual speed of a plotter in completing a job. Difficult to measure, but it represents a plotter's ability to process information and then cut an image.

Tint — A colour made lighter than the original by adding white to it.

Tone — The effect on a colour brought about by blending it with another colour.

Transfer tape — Medium-tack adhesive-coated translucent paper, placed on weeded vinyl images still on the original carrier liner; the tack of the tape is stronger than the adhesion of the vinyl to the coated liner, so the image is pulled off the liner in a transfer to another surface.

Translucent — The property of a substrate, vinyl, paint or ink to allow the passage of some light through it without being transparent.

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UV-curing — Printing process in which a lamp emitting ultra violet (UV) rays is used to transform monomer-based liquid inks (deposited onto a substrate) into polymer-based solid inks. Commonly used process in many digital flatbed printers.

UV resistance — Ability to withstand decay due to the damaging effect of the ultraviolet rays of the sun.

Vacuum forming — Taking a flat sheet of plastic material and giving it dimension by placing it in a mould, heating it until it's flexible and then withdrawing the air in the mould, creating a vacuum. See 'thermoform'

Vector — In computerised signmaking, a line segment between two co-ordinates, on which a knife or tool path can be created for plotting or routing.

VHB —Tape produced by 3M. Very High Bond joining systems are applied between mated parts to eliminate the need for mechanical fasteners or welded attachments. This tape is available in many grades and thicknesses.

Vinyl — Polyvinyl chloride (PVC) film that, in sign making, is backed with an adhesive that will create a strong bond to a surface when pressure is applied.

VOCs — Volatile Organic Compounds (VOCs) are petroleum- based chemical compounds with high vapour pressure and low water solubility (evaporate easily). Commonly found in industrial solvents, including those used as carriers in solvent-based inks. VOCs are considered toxic, and airborne VOCs are federally regulated in some industries.

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Wall mount — A single-face sign mounted on a wall. Another name for a wall sign.  

Wax transfer — A method of heating a coloured wax material and printing it on to vinyl.

Weed — Process of peeling extraneous vinyl (or matrix) away from a plotter cut, leaving only the sections representing the final image. Pulling the extra vinyl away in one quick stroke is known as rip weeding.

X axis — Theoretical horizontal line providing a lengthwise reference point for plotters and routers.

Y axis — Theoretical vertical line providing a longitudinal reference point for plotters and routers.

Z axis — Theoretical line providing a depth reference point for routers.