Goniophotometry
Encyclopedia
Goniophotometry or goniometric optical scatter measurement is the technique of measuring the angular
distribution of light
, possibly wavelength
-dependent, scattered
from a surface.
Goniophotometry is used to evaluate the gloss
of paint
s and other surface finishes.
Angle
In geometry, an angle is the figure formed by two rays sharing a common endpoint, called the vertex of the angle.Angles are usually presumed to be in a Euclidean plane with the circle taken for standard with regard to direction. In fact, an angle is frequently viewed as a measure of an circular arc...
distribution of light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
, possibly wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
-dependent, scattered
Scattering
Scattering is a general physical process where some forms of radiation, such as light, sound, or moving particles, are forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which they pass. In conventional use, this also includes deviation of...
from a surface.
Goniophotometry is used to evaluate the gloss
Gloss (paint)
Paint and other finishes come in a variety of finish gloss levels, which correspond to different levels of specular reflection.Some common names for levels of gloss include: flat, matte, eggshell, satin, silk, semi-gloss, high gloss. These terms are not standardized, and not all manufacturers use...
of paint
Paint
Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...
s and other surface finishes.