Although the boundary between the two regions is indecisively distinguished, it depends on the dominant wavelength
([lambda]) emitted by the source and near-field region is generally defined as within a quarter wavelength.
Integrating Tube systems produce highly accurate and repeatable measurements of total flux, chromaticity, peak wavelength, dominant wavelength
, CCT and CRI.
The light of shorter wavelengths (blue and green) is seen to be less attenuated by scattering than that of longer wavelengths (amber with the dominant wavelength
close to that of high pressure sodium lamps that presently are widely used in street lighting, yellow-green, and red).
Hue is the dominant wavelength
of a particular color, though in imaging we tend to use red, green, and blue filters to mimic our eyes' response to light.
For example, LEDs may be binned according to any combination of forward voltage, luminous flux, correlated color temperature (CCT) for white LEDs, or dominant wavelength
for color LEDs.
Specifically it would be that the dominant wavelength
is perceived as the color under certain defined conditions of viewing.
Lightness Compression, Dominant Wavelength
, and Hue Perception
Both the XT-24 and XT-27 chips are offered with a typical dominant wavelength
Following the prevailing opinion, hue perception should be strongly determined by dominant wavelength
(see, for example, Sanders & McCormick, 1993, pg.
Optical measurements able to be taken by the device include total radiant and luminous flux, peak wavelength, dominant wavelength
, CIE purity and CIE chromacity.
Since the difference of a single dominant wavelength
bin can be noticeable to the human eye, lighting designers with specific requirements in their LEDs as a component of their lighting designs can specify a binning code or binning number to ensure the LEDs perform with consistency.
These include luminous flux, dominant wavelength
or color temperature, mean time between failure (MTTF) and flux degradation.