Experimental Validation of Colour Mixing in CIE XYZ Colour Space with LED Lamps

The concept of colour mixing in the CIE XYZ colour space for light sources has long been known; however, experimental validations with actual sources are seldom reported. This paper aims to validate the concept with light emitting diode (LED)-based lamps that are commonly available in the Indonesian market. The methods are as follows: Three bulb-type LED lamps, each with nominal correlated colour temperature (CCT) of 3000, 6500, and 10000 K, were measured individually with spectrocolorimeter in order to obtain the CIE 1931 chromaticity values. Based on the results, mixed chromaticity of all combinations of those three lamps were predicted using Grassmann's Law, which in turn were compared with the actually measured values of the combinations. The comparisons suggest that there is no significant difference (95% confidence level) between the chromaticity using colour mixing prediction and measurement results.