History
For more details on this topic, see Standard illuminant#Illuminant series D.The CIE introduced three standard illuminants in 1931:
- A: Incandescent bulb simulator
- B: Daylight simulator (direct)
- C: Daylight simulator (shade)
B and C were derived from A by using liquid filters. The approximation to real light this provided was found lacking, so in 1967 the CIE accepted a proposal by Judd, MacAdam, and Wyszecki for a new series of daylight simulators, bearing the initial D.
Read more about this topic: Illuminant D65
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