[E.2] GLOSSARY: LIGHTING ✅

Argand Lamp

Lamp invented by a Swiss in 1783. Had a round wick with provision for the introduction of air inside the wick as well as around the outside

Astral Lamp

Oil lamp with swinging tubular arms, generally furnished with an Argand burner. Used in the early 19th C

Adaptation

Process when an eye adjusts to a change in light level

Ambient Light

Indirect general light

Baffle

Opaque or translucent element used to shield a lamp from view or to absorb unwanted light

Ballast

A device used with HID and fluorescent lamps to establish the circuit conditions necessary to start and operate the lamp

Bare Lamp

An unshielded light source

Blinding Glare

Intense glare that blinds a person for a short period of time

Concealed Light

Any artificial light source concealed behind a decorative facing which allows the light to diffuse over its edges. Cove and valance lighting are examples of concealed light

Contrast

Difference in luminance between an object and its background

Dichroic Mirror

Optical filter that selectively reflects some wavelengths, while transmitting others

Diffuse Reflection

One that appears scattered, either in reflection or transmission

Dimmer

Device used to regulate the intensity of light from a lamp

Directional Light

The light that is focused and forced to travel in a particular direction either by a reflector or baffle. This may be a spotlight of any sort or a lamp with an opaque shade (not translucent) so that the light goes in a particular direction

Disabling Glare

Glare that reduces visibility and visual performance

Discomfort Glare

Annoying glare that does not reduce visibility and visual performance

Eyeball

Recessed or semi-recessed lighting unit with a rotating spherical element that may be turned to project light in any direction below the ceiling line

Fiber Optics

A way of transmitting light through long flexible glass or plastic fibers, using the principle of total intern refraction

Filter

Device that changes the quality of light affecting the magnitude and/or spectral make-up

Fluorescence

Emission of light during the absorption of radiation of a different wavelength

Illuminance

Density of light on a surface

Projector

Lighting unit that concentrates light in a limited angle and intensifies it

Shielding

General term used to describe devices that block, diffuse, or redirect light such as louver or a lampshade

Spill Light

Any stray light outside the main concentration of the beam controlled by louvers or baffles

Veiling Reflection

Glare, where reflection reduces contrast and so prevents detail being discerned

Work Plane

Usually the horizontal surface at which a task is performed, and at which light levels are specified and measured