Sign Making Glosary

General

Message: Information or instructions to be conveyed.

Sign (1): Graphic presentation of a message.

Sign (2): Device on which sign (1) is conveyed.

Fascia sign: A sign (2) which is fixed on vertical surfaces such as a wall. It will not normally have a significant projection from that wall. It is intended to be viewed from a position opposite to the mounting surface.

Projecting Sign: A sign (2) which projects at right angles to a wall and is designed to be viewed from up or down the street. Projecting signs usually have a sign (1) on either side.

Box Sign: A sign (2) which is totally enclosed and which may have internal lighting. Most box signs have translucent plastic portions carrying a sign (1) on one or more faces.

Signing: Planning, manufacture, installation, management and use of signs (1) and (2).

Sign-writing: Inscribing a sign.

Sign Elements

Text: Message conveyed in characters only.

Typeface: Set of characters derived from one basic design.

Roman alphabet: Alphabet that consists of upright characters.

Italic alphabet: Alphabet that consists of sloping characters.

Serif: Small terminal stroke at the end of a main stroke of a character.

Sans serif: Character or typeface without a serif.

Character: Letter, numeral or punctuation mark.

Upper case letter: Capital letter in an alphabet.

Lower case letter: Letter in an alphabet other than an upper case letter.

Ascender: Part of a lower case letter that ascends above the mean line.

Descender: Part of a lower case letter that descends below the base line.

x height: Height of a lower case letter "x" used as a unit of measure.

Cap height: Height of an upper case letter used as a unit of measure.

Numeral height: Height of a numeral used as a unit of measure.

Stroke width: Width of a letter or numeral that determines the boldness of a typeface.

Letter space: Horizontal space between characters.

Word space: Horizontal space between words.

Line space: Vertical space between adjoining lines of text.

Symbol: Pictorial representation used in a sign (1).

Sign Layout

Landscape format: Proportion of a sign (2) in which height is appreciably shorter than width.

Portrait format: Proportion of a sign (2) in which height is appreciably longer than width.

Message zone: Zone on sign allocated to a message.

Text zone: Area of a message zone allocated to text.

Sign tile: Hypothetical rectangular zone that may contain a character, symbol or void for a word space, used to achieve consistent spacing.

Symbol zone: Area of a message zone allocated to a symbol.

Sign panel: Area within a sign (1) that has its own distinctive background.

Sign background: Area of sign (1) on which the message is displayed.

Margin: Space between the message zone or symbol and the outer edge of a signboard.

Border: Band that defines the outer edge of a sign (1).

Visual Aspects

Legibility: Ease with which one property of characters or symbols can be distinguished from another.
Conspicuity: Capability of one entity in the visual field to be more easily noticed than the surrounding information.

Central line of vision: Theoretical line of vision of a person looking straight ahead.

Displacement: Distance that a sign (1) (2) is offset from the central line of vision.

Perceived size: Size that a character or symbol appears to be because of its relationship to its surroundings, as against its actual size.

Resolution: Ability of the visual system to resolve small details.

Glare: Glare results from areas of high brightness in the visual field and can cause discomfort, irritation and obscuration of the message.

Halation: An effect caused by extreme contrast between the illuminated and unilluminated portions of a sign and which affects the ability of the eye to focus on that sign. The effect is also dependent on colour.

Luminance: A measure of the brightness of a sign. It is usually applied to signs with a significant surface area (not point sources) and is expressed in terms of Candelas per Square Metre.

Luminance Ratio: Any sign face will have parts which have a higher luminance than other parts. The ratio of the luminance of the brighter parts to that of the less bright parts is called the luminance ratio. If this is too large, the illumination of the sign face will appear patchy.

Sign Types & Construction

Sign blank: Signboard prior to the application of a message.

Sign face: That part of a sign (2) that bears the message and margins and any border.

Signboard: Sign (2) that has a flat surface on which the message is depicted.

Recessed message: Sign (1) in which the message is produced by setting cut-out characters or symbols behind similar cut-out letters or symbols in a signboard.

Flush message: Sign (1) in which the characters or symbols are flush with the surface of a signboard.

Proud message: Sign (1) in which the characters or symbols are raised from the surface of a signboard.

Subsurface message: Sign (1) in which the message is placed behind the surface of a transparent sign face.

Sign face: The front part of a sign.

Flange: A frame for the sign face. This usually consists of a thin strip of metal, attached to the return of the sign and is designed to retain the plastic face.

Bevel: A flange may be simply flat or may, more attractively, be fitted at an angle to the face. Depending on whether the angle is positive or negative, the flange will be described as having a bevel or an inverted bevel.

Return: That part of a sign letter or box sign which connects the front face to the back of the sign and provides the sign with a suitable depth.

Poly-methyl methacrylate (Acrylic): A very stable plastic material, widely used in sign manufacture. Examples of trade names for acrylic plastics include Perspex, Plexiglas and Oroglas.

Polycarbonate: A plastic material with greater impact strength than acrylic. Examples of trade names for polycarbonate include Makrolon and Lexan.

Flexible face material: Thin translucent sheeting, usually of PVC or polyester material, reinforced by internal fibres, which may be used as a sign face and decorated by a legend. The material has the advantage of being able to cover large areas in one piece.

Halo: A type of sign construction where the light generated within the letter or emblem is allowed to floodlight the surface on which the sign is mounted. The letter or emblem appears as a dark shape against a lighted background.

Exposed tubing: Sign (2) where the surface of the tube(s) is visible.

CAD: Computer aided design. The use of a computer with suitable graphics software to design signs and their legends.

CAM: Computer aided manufacture. The use of a computer to control the operation of a machine tool. Such a tool may be linked to a computer aided design station and the combination is then known as CAD-CAM.

Variable Signs

Variable sign: Sign (2) where the message may be changed readily.

Variable plank sign: A variable sign that consists of a frame within which pre-printed sign planks can be assembled.

Variable character sign: Variable sign that consists of a frame within which individual characters can be assembled.

Roller blind sign: A variable sign that consists of a number of messages on a roll of material. A message is displayed by winding the roll to therequired position.

Hinged flap sign: Variable sign that consists of a number of double-sided hinged flaps with characters or symbols, arranged so that any two adjacent flap faces may be displayed.

Rotating facet sign: A variable sign that consists of sign planks with multiple faces that can be rotated to display a different face and message.

Matrix sign: A variable sign on which messages are formed by the controlled display of individual units of dots, bars or other shapes arranged on a pre-determined grid.

Seven-bar sign: A variable sign on which numerals are formed by the controlled display of seven individual bars. The bars are arranged in a pattern to form the seven parts of a figure 8.

Electro-mechanical sign: A matrix or seven-bar sign in which a disc or bar is turned electro-mechanically to display either of its two faces. One face is coloured to blend into the background and the other is coloured to contrast with the background.

Liquid crystal display sign: A matrix or seven-bar sign in which the individual elements are electro-optic devices whose optical transmission is varied by the presence of a control voltage.

Fibre optic sign: A sign in which light is transmitted through optical fibres, the ends of the fibres being arranged to form either the dots of a matrix sign or the outline of a message.

Light emitting diode sign: A matrix or seven-bar sign that uses a grid of light emitting diodes.

Video sign: A variable sign displayed on a television screen.

Video matrix sign: A matrix sign in which the individual dots are formed from cathode ray tubes.

Illuminated Signs

Illuminated sign: A sign (2) that emits or reflects light.

Fluorescent sign: A sign (2) that absorbs ultra-violet light and emits visible light.

Self-luminous sign: A sign (2) that emits light because it contains a radioactive gas and does not rely on an external power source.

Phosphorescent sign: A sign (2) that uses phosphors as a pigmentation and emits light for a period of time after the energy source has been removed.

Retro-reflective sign: A sign (2) that reflects light preferentially in the direction of a light source.

Power illuminated sign: A sign (2) in which the characters or symbols on the sign face are lit by a device connected to a power source.

Neon sign: A sign (2) where the illumination is obtained from cold-cathode tubing, such tubing may be neon tubing or mercury tubing.

Internally illuminated sign: A power illuminated sign in which the light source is placed within the sign (1).

Externally illuminated sign: A power illuminated sign in which the light source is placed in front of the sign face.

Filament lamp sign: A power illuminated sign that uses tungsten filament lamps.

Fluorescent tube sign: A power illuminated sign that uses tubular fluorescent lamps.

Secret sign: An internally illuminated sign the message of which cannot be seen when the light source is switched off.

Mounting of Signs

Suspended sign: A sign (2) that is supported from above.

Projecting sign: A sign (2) that projects from a vertical surface.

Post mounted sign: A sign (2) that is fixed to one or more sign poles.

Sign pole: A post used to support a sign (2).

Finger post sign: A post mounted sign that functions as a direction sign and has one or more sign planks that point in the general direction of the destinations.

Wall mounted sign: A sign (2) intended to be mounted onto a wall surface.

Lamps

Note: Light is produced by lamps but, because of they are made as long thin tubes, most discharge lamps used by the sign industry are referred to as "Tubes".

Luminous-discharge tube: Any tube, or other vessel or device, which is constructed of translucent material, hermetically sealed, and designed for the emission of light arising from the passage of an electric current through a gas or vapour contained within it. The tube may be with or without a fluorescent coating.

Neon tube: A luminous-discharge tube where the light is produced by the passage of an electric current through neon gas. The light output is a combination of a large number of line spectra, mainly in the orange/red region.

Note: Since the electric current also produces emissions in the ultra-violet region, the characteristic "neon" colour of the discharge may be modified by theaddition of a fluorescent phosphor to the inside wall of the tube.

Mercury tube: A luminous-discharge tube where an ultra-violet emission is produced by the passage of an electric current through mercury vapour. The light from such tubes is produced by the action of the ultra-violet radiation on a fluorescent phosphor coated on the inside wall of the tube. The presence of a gas, such as argon or an argon/neon mixture, is also required for the correct operation of a mercury tube.

Note: The term "neon tube" is also used generically to refer to both neon tubes and mercury tubes.
Electrode: A device fitted at either end of a tube to allow the electrical discharge within the tube to be connected to an external circuit. When an electrode is connected to the negative pole of a supply, it will emit electrons and is called a cathode. When it is connected to the positive pole of a supply, it will receive electrons and is called an anode.

Cold cathode: An electrode which emits electrons by a process known as secondary emission. The cathode fall voltage of such an electrode may be reduced by means of an emissive coating.

Hot cathode: An electrode which, during normal operation, has its temperature raisedto a red heat. It is coated with an emissive material and emits electrons by a process known as thermionic emission.

Phosphor: A fine powder which is coated on the inside of tubing and hasthe property of emitting visible light when irradiated by ultra-violet energy. Different phosphors emit light of different colours.

Lamp Manufacture

Pumping: A process to remove all air and other impurities from the tube, before it is filled with the desired gases. The process is usually combined with heating the tube to ensure that all impurities are released from its components.

Bombard pumping: A process whereby, during the pumping operation, the temperatures of the tube and the electrodes are raised to the desired level by passing a large electric current through the tube, firstly in air and then in a suitable gas such as helium.

Oven pumping: A process whereby the temperature of the tube is raised during pumping by placing it within an oven. The electrodes are usually separately heated by means of a high frequency induction heater.

Electrical

Low voltage: A voltage normally exceeding 50 V a.c. or 120 V d.c. whether between conductors or to earth, but not exceeding 1000 V a.c. or 1500 V d.c. between conductors, or 600 V a.c. or 900 V d.c. between conductors and earth.

High voltage: A voltage exceeding 1000 V a.c. or 1500 V d.c. between conductors, or 600 V a.c. or 900V d.c. between conductors and earth.

Creepage distance: The shortest path between two conductive parts or between a conductive part and the interior surface of the installation,measured along the surface of the insulating material. Note The interior surface of the installation is the inner surface of the enclosure, considered as though a metal foil were pressed into contact with all inner surfaces of the insulating material.

Clearance: The shortest distance between two conductive parts or between a conductive part and the interior surface of the installation, measured through the air.

Live part: A conductor or conductive part intended to be energised in normal use, including the neutral conductor but, by convention, not a P.E.N conductor.

Input end (low-voltage circuit): Refers to the part of the device between the feeding point and the input terminals of the transformer, convertor or invertor.

Output end (lamp circuit): Refers to the part of the device between the output terminals of the transformer, convertor or invertor and the discharge tubes inclusive.

Insulating sleeve: Insulation designed to be placed over the exposed high-voltage connections at tube electrodes or over cable-end insulators.Note: Some types of insulating sleeves were previously called "bell glasses".

Control Gear

Ballast: A unit inserted between the supply and one or more luminous discharge tubes which by means of inductance, capacitance or a combination of inductance and capacitance serves mainly to limit the current of the tube(s) to the required value. The ballast may consist of one or mor separate components. It may also include means of transforming the supply voltage and arrangements which help provide the starting voltage, prevent cold starting, reduce stroboscopic effects, correct the power factor and/or suppress radio interference.

Transformer: A unit for the conversion of an a.c. supply at one voltage and frequency to an a.c. supply at a different voltage and the same frequency.

High-reactance transformer: This is sometimes called a "stray-field transformer". It includes a construction which combines the function of a step-up transformer and ballast

Invertor: An electric energy transducer that converts unidirectional current to alternating current.

Convertor: A unit for the electronic conversion of an a.c. supply at one frequency to an a.c. supply at another frequency. The voltage may or may not be altered during the conversion.

Power-factor correction: A method of reducing the supply current of a reactive circuit to a value which is close to that which would be expected from the power of the circuit. With inductive circuits, this will usually be achieved by connecting a suitable capacitor across the supply terminals.

Earth-leakage protective device: A device which will disconnect the mains supply to a transformer or transformers in the event of a short circuit between any part of the secondary high voltage circuit and earth. The device is in two parts, a sensor and a protective switch, as defined below. Note: The functions of a the sensor and protective switch may be combined in one unit.

Open-circuit protective device: A device which will disconnect the mains supply to a transformer or transformers in the event of an interruption of the secondary high voltage circuit.

Sensor: That part of a protective device which detects the presence of a secondary earth fault and/or an open circuit condition and provides a signal to operate a protective switch.

Protective switch: That part of a protective device which disconnects the mains supply to a transformer or transformers. It is operated by an electrical signal obtained from a sensor.

Animation

Animation: The switching on and off of various parts of a sign (2) to provide the illusion of movement.

Flasher: A device for switching one or more lamp circuits on and off. The sequence of switching of the various parts of a sign may be suitably arranged to provide animation. Note: Although flashers may be constructed to provide any animation sequence, certain popular sequences are available. These include flashers to provide border chasing and spelling effects.

Flashing sequence: The order in which the contacts (or semiconductor switches) of a flasher are operated and the time intervals between their operation.

Dimming: The process of reducing the light output of a lamp or lamps from a high value to a low value. The term is also used for increasing the light output from a low to a high value.

Personnel

Installer: The person, qualified in sign installation practice, who takes responsibility for the quality of the installation and its testing.

Authorised person: A person employed, appointed or selected by his employer to carry out defined duties, such person being a competent person.

Competent person: A person with sufficient training, knowledge or experience to prevent danger, having regard for the degree of supervision which is appropriate to the nature of the work.

Safety

Ensuring electrical safety: The process of switching off the electrical supply to an installation, ensuring that the supply cannot be switched back on again, checking that the supply to the installation is dead and then proving that the instrument used to do this is reading correctly.

Maintaining electrical safety: The process of "Ensuring electrical safety" followed by the application of means to ensure that circuit cannot inadvertently be made live again. Note: An example of a technique of "Maintaining safety" would be the bonding of the HV terminals of a transformer to earth by means of a connection(s) which cannot be removed except by the use of a tool.

Dead: An electrical supply which is at or about zero potential and disconnected from any live system.

Earthed: An electrical circuit which is connected to the general mass of earth in such manner as will ensure at all times an immediate discharge of electrical energy without danger.

Live: An electrical circuit which is electrically charged.

Quality Systems

Quality policy: The overall quality intentions and direction of an organisation as regards quality, as formally expressed by top management.

Quality management: That aspect of the overall management function that determines and implements the quality policy.

Quality system: The organizational structure, responsibilities, procedures, processes and resources for implementing quality management. The requirements for a quality system are given in BS 5750.

Quality control: The operational techniques and activities that are used to fulfil requirements for quality.
Quality assurance: All those planned and systematic actions necessary to provide adequate confidence that a product or service will satisfy given requirements for quality.