Light Sources | SPD Curves | National Gallery, London

Find the chromaticity xy co-ordinates of the test source from its calculated CIE 1931 color space XYZ values.
Determine the correlated color temperature (CCT) of the test source and select the appropriate black body reference source.
Illuminate the fifteen CQS test colour samples, alternately using both sources.
Calculate the CIE 1976 (L*, a*, b*) color space coordinates of the light reflected by each sample.
Calculate the various ΔC*ab and ΔE*ab values as indicated in the table below.
Calculate the overall CQS using the equation: CQS = 10 * log(exp(((100-ScalingFactor*OverAllΔE*abSF))/10)+1)

Illuminant	VS01	VS02	VS03	VS04	VS05	VS06	VS07	VS08	VS09	VS10	VS11	VS12	VS13	VS14	VS15
x	0.6495	0.5958	0.5664	0.5337	0.4883	0.4435	0.3656	0.3386	0.3372	0.3052	0.2967	0.3732	0.5021	0.5551	0.5997
y	0.3263	0.3795	0.4162	0.4429	0.4775	0.4995	0.5238	0.4721	0.4298	0.3840	0.3477	0.3340	0.3455	0.3473	0.3372
u	0.4625	0.3745	0.3302	0.2946	0.2519	0.2189	0.1710	0.1695	0.1802	0.1744	0.1804	0.2384	0.3270	0.3666	0.4102
v	0.3486	0.3579	0.3639	0.3667	0.3695	0.3697	0.3674	0.3546	0.3446	0.3293	0.3171	0.3200	0.3375	0.3440	0.3460
L*	47.79	66.32	72.75	78.53	77.14	64.94	53.17	52.01	52.66	42.46	34.09	35.47	51.24	62.39	54.85
a*	56.79	40.73	24.09	8.46	-13.52	-27.22	-44.46	-41.45	-34.13	-28.10	-19.47	-1.02	25.08	41.05	49.50
b*	39.18	54.40	71.63	69.17	58.37	35.80	10.40	-15.31	-29.57	-43.18	-47.00	-41.46	-19.35	-0.56	15.07
C*ab	68.99	67.96	75.57	69.68	59.92	44.97	45.66	44.18	45.16	51.52	50.87	41.47	31.68	41.06	51.74

Black Body	VS01	VS02	VS03	VS04	VS05	VS06	VS07	VS08	VS09	VS10	VS11	VS12	VS13	VS14	VS15
x	0.6492	0.5956	0.5665	0.5339	0.4883	0.4432	0.3647	0.3370	0.3352	0.3029	0.2942	0.3701	0.4998	0.5534	0.5986
y	0.3258	0.3788	0.4155	0.4421	0.4765	0.4983	0.5217	0.4687	0.4257	0.3791	0.3424	0.3292	0.3426	0.3455	0.3360
u	0.4628	0.3749	0.3307	0.2951	0.2523	0.2191	0.1710	0.1696	0.1803	0.1745	0.1805	0.2383	0.3271	0.3666	0.4103
v	0.3484	0.3577	0.3638	0.3665	0.3693	0.3694	0.3669	0.3537	0.3434	0.3276	0.3151	0.3181	0.3363	0.3432	0.3455
L*	47.86	66.35	72.75	78.51	77.10	64.91	53.15	52.01	52.68	42.49	34.12	35.50	51.28	62.43	54.90
a*	56.69	40.58	23.97	8.35	-13.59	-27.33	-44.55	-41.46	-34.07	-27.94	-19.23	-0.80	25.19	41.00	49.41
b*	39.25	54.47	71.76	69.56	58.65	36.15	10.71	-15.04	-29.39	-43.05	-46.95	-41.55	-19.49	-0.63	15.07
C*ab	68.95	67.92	75.66	70.06	60.20	45.32	45.82	44.11	44.99	51.32	50.74	41.56	31.86	41.00	51.66

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