And, suffice it to say, different spectral power distributions with the same luminance and correlated color temperature (even with identical chromaticity coordinates) can produce different experiences along the dimensions of brilliance and colorfulness.
With such metrics, it is possible to design the spectral power distributions of light sources for image projectors or general illumination to minimize the inter-observer differences in appearance of certain types of objects or of the lighting itself.
When CRI is applied to highly-structured spectral power distributions
(SPDs), such as those produced by some light emitting diodes (LEDs), the numerical scores do not always corroborate visual impressions.
It can be seen that the spectral power distributions of the two LED sources (shown for 1 A and 2 A feeding currents) are well within the spectral responsivity functions for both UV meters.
Also, the spectral power distribution of the excitation 365-nm sources has not been standardized which is a must if the realized spectral responsivity function of the UV meter is different from the standard function.
Figure 3 compares the spectral power distributions for the cool white fluorescent lamp and xenon arc with Window Glass Filter vs.
That is, the lamp's output does not match the spectral power distribution of other commercially-used light sources or sunlight through window glass.
Based on this information, we provide a computation of potential hazard doses for a number of lamps with differing spectral power distributions for both candidate action spectra.
This factor is calculated by normalizing the spectral power distribution (SPD) of concern to one lumen, and then weighting the resultant normalized SPD at each wavelength by a spectral hazard function and subsequently integrating the weighted function over wave lengths.
The luminaire's spectral power distributions
are presented in Fig.
In mathematical terms, these programs very coarsely sample the spectral power distributions
of the light sources and the spectral reflectance and transmittance distributions of the surface materials.