HOW to calculate the Color Rendering Capacity ?

* The key to calculating the color
rendering capacity of a given spectral power distribution is to

calculate the volume of the color solid
correspondinr to the given spectral power distribution.

Suppose the calculation is conducted in the CIE 1976
u*v*L* color space..

* Using the spectral reflectance curves of special type that
consist of either one single reflecting

band or one single absorbing band with the values of
spectral reflectance being either 0.0 or 1.0,

in conjunction with the given spectral power
distribution , a group of chromaticity coordinates

(u*v*) can be calculated for one specified value of
L* .

* A polygon can be constructed with this group of chromaticity
coordinates (u*v*) for the

specified value of L*. And the area of the polygon
can be calculated.

* The sum of those areas of the 9 polygons associated
respectively with L*=10,20,...,and 90 comes

, approximately, to the volume of the color solid
corresponding to the given spectral power

distribution .

* A software CRC99 has been available for calculating the Color
Rendering Capacity of any

kind of light sources.

Download a simplified version
of CRC99 to calculate the

color rendering capacity of any light source: CLICK HERE

Note:

1 Download the file Crc99.zip (18KB) to drive C:

2 Extract the file to folder C:\Crc99\

3 Run C:\Crc99\Crc99.exe, that is all.

A printout of CRC99 calculation results: