The spectral composition of light has been linked to various non-image-forming responses besides visual photoreception. Accordingly, simulation tools must incorporate the spectral composition of light to account for such responses. A simulation tool was developed which uses N-step algorithm and subdivides the (red, green, and blue) RGB bands into multiple channels. This research intends to validate the tool for different lighting scenarios. A physical model was constructed in which the integral irradiance from 380 nm to 780 nm was measured for three scenarios: diffuse daylight, electric light with variable correlated colour temperature and a combination of both. All three scenarios were simulated with 3, 9, 27 and 81 channels. For scenarios with electric light and combination of daylight and electric light, the nine-channel simulation improved the mean absolute percentage error (MAPE) by 13.9% to 33.9% compared to the three-channel simulation. For continuous daylight, there was only a small improvement of 0.4% when increasing from 3 to 27 channels. In comparison to 9 channels, 27 channels slightly improved MAPE in all the scenarios but substantially increased the simulation time. Increasing the number of channels to 81 is likelier to bring a contribution to more complex scenarios than that presented in this study.

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Light affects humans beyond only image formation. Several studies have reported that light can increase daytime alertness and can therefore be positively utilized to counter daytime fatigue and increase productivity in workspaces. This systematic review summarized and analysed relevant literature that investigated the daytime alerting effect of light. Using keywords “alertness” and “light” in the title we retrieved a total of 142 studies via three search engines. Out of 142 studies, only 26 investigated the alerting effect of light during daytime. Six studies were excluded from the review based on the exclusion criteria. We reviewed twenty articles from the year 1991 until 2022 that have investigated the alerting effect of polychromatic and monochromatic light sources. Only seven out of twenty studies found an alerting effect that was recorded through positive self-assessment or enhancement of cognitive processes. The studies in which the lighting application would be transferrable for office use were highlighted. A specific common trend regarding the enhancement of alertness was not detected, as different lighting conditions and protocols were applied in the reviewed studies. More studies that investigate the effect of polychromatic light with intensities and spectral compositions that are suitable for application in realistic working environments are necessary to determine whether the daytime alerting effect of light will be significant.