sources that provide both uplight and
downlight.
Veiling reflection: a reflection of incident light
that partially or completely obscures the
details on a surface by reducing its contrast.
See alsoreflected glare.
Visual comfort: the degree of visual satisfaction
produced by the luminous environment,
resulting from the reduction of glare and dis-
tracting luminance in the field of view.
Visible spectrum: wavelengths of electromag-
netic energy, ranging from approximately
380 nanometers (nm) to 760 nm.
Volt: the standard unit of measurement for elec-
trical potential; when applied across a resis-
tance of one ohm, it will result in a current
flow of one ampere.
Wall-washer: a luminaire with an asymmetric
distribution used for illuminating vertical sur-
faces from ceiling to floor without noticeable
variation in intensity.
Watt: the unit of electrical power; it is equal to
the power produced by a current of one
ampere across a potential difference of one
volt.
Wattage: the amount of power expressed in
watts.
Wavelength: the distance between one peak or
crest of a wave of light, heat, or other energy,
and the next corresponding peak or crest.
Workplane:the plane on which visual tasks are
usually done; a horizontal plane 2 ft 6 in.
above the floor, unless otherwise indicated.INTERIOR LIGHTING FOR DESIGNERS