22 August 2006
glossy surfaces in the field of view.
a general term for the process
by which the incident flux leaves
(stationary) surface or medium from the incident side without change in frequency.
a device used
to redirect the flux from
by the process
Scotopic Vision vision mediated essentially or exclusively by the rods. It is generally
associated with adaptation to a luminance below about 0.034 cd/m.
Self-Ballasted Lamps any arc discharge lamp of which the current limiting devices is
an integral part.
Spacing for roadway lighting, the distance between successive lighting units,
measured along the centerline of the street.
Spacing-to-Mounting-Height Ratio the ratio of the actual distance between
luminaire centers to the mounting height above the work plane.
Sun Bearing the angle measured in the plane of the horizon between a vertical plane
at a right angle to the window wall and the position of this plane after it has been rotated
to contain the sun.
Suspended (pendant) Luminaire a luminaire that is hung from a ceiling by supports.
Table Lamp a portable luminaire with a short stand, suitable for standing on furniture.
Torchiere an indirect floor lamp that sends all or nearly all of its light upward.
Translucent transmitting light diffusely or imperfectly.
Transmission a general term for the process by which incident flux leaves a surface
or medium on a side other than the incident side, without change in frequency.
Transmittance the ratio
of the transmitted flux
to the incident flux.
Transmittance, Visible(Tvis) the percentage of the visible spectrum transmitted.
Transparent having the property of transmitting rays of light through its substance so
that bodies situated beyond or behind can be distinctly seen.
a long recessed lighting unit usually installed with the opening flush with the
Tungsten-Halogen Lamp a gas-filled tungsten filament incandescent lamp containing
a certain proportion of halogens in an inert gas whose pressure exceeds 3 atm.
Valance a longitudinal shielding member mounted across the top of a window or
along a wall (and is usually parallel to the wall) to conceal light sources, giving both
upward and downward distributions.
Valance Lighting lighting comprising light sources shielded by a panel parallel to the
wall at the top of a window.
Veiling Reflection regular reflections that are superimposed upon diffuse reflections
from an object that partially or totally obscure the details to be seen by reducing the