Effects of Light’s Colour Temperatures on Visual Comfort Level, Task Performances, and Alertness among Students

Abstract

Introduction: Correlated colour temperatures (CCT) of the light source in indoor environment plays an imperative role in addressing both psychological and physiological functions of the occupant. As one of the determinants of lighting quality, CCT are off particular importance which affects quality of work and in classroom learning. Objective: The aim of this study is to determine the effects of warm white light (WWL) (CCT = 3,000K), cool white light (CWL) (CCT = 4,000K) and artificial daylight (DL) (CCT=6,500K) on the performances, subjective alertness level, visual comfort level and preferences of student in Faculty of Medicine and Health Sciences, Universiti Putra Malaysia. Methodology: A laboratory controlled experiment was conducted on total of 47 undergraduate students volunteered to participate in a series of test under three coloured light sources. FrACT software was used to assess visual task performance, modified OLS questionnaire was used to evaluate subjective comfort level and preferences, typing test and KSS alertness level monitoring was conducted. Result: Significant increase was observed in subjective alertness level (p=0.041) and computer-based performances (p=0.001) under DL condition in relative to WWL condition. In terms of typing performances, respondents performed significantly better in term of typing speed under CWL than DL and WWL. Least typing errors were made under DL, followed by CWL and WWL. CWL is the most preferred (p=0.001) and most comfortable (p=0.011) CCT environment where subjects indicated the ability to perform task longer in this coloured-lit environment. Conclusion: The study concludes that the CWL and DL were more beneficial for alertness level and academically activities for both computer-based and paper-based activities.

Comparing task performance, visual comfort and alertness under different lighting sources: an experimental study

“…Experimental studies have shown that exposure to higher levels of light at night leads to suppression of melatonin secretion, increase of physiological arousal, higher levels of mental consciousness and improvement of alertness and cognitive performance (Hawes et al, 2012[ 13 ]; Min et al, 2013[ 26 ]). Research findings have further demonstrated that increasing the color temperature of the light sources improves cognitive performance of night shift workers, visual performance and visual comfort of the students and sleep quality, performance and behavior of industrial staff (Viola et al, 2008[ 39 ]; Chellappa et al, 2011[ 7 ]; Shamsul et al, 2013[ 36 ]).…”

Integrating building information modeling and virtual reality development engines for building indoor lighting design

“…Moreover, the illuminance levels on the desks are approximately 700 to 800 lx. When lights for windows zone are switched off, the results revealed that the illuminance levels on the working desks in the windows zone are in the range of 450 to 650 lx, which is more than the minimum lighting requirement in the office (Shamsul et al, 2013). In addition, the power usage of electric lights is 720 W, and the energy consumption is 5.76 kWh.…”

“…Designers must ensure that the visual comfort parameters comply with the standard of lighting design. Regarding human visual perception, the most important variables are CCT and illuminance level (Shamsul et al, 2013). Visual perception is defined as an interpretation capability of visual sensation when people visually perceive their surrounding environment.…”

“…Correlated color temperature describes the characteristics of light colors. Color temperature plays a particularly important role in both the physical properties of light and the physiological and psychological response of humans when light enters the eyes (Descottes & Ramos, 2011;Shamsul et al, 2013).…”

RoomFort: An Ontology-Based Comfort Management Application for Hotels

“…More recently, it was also demonstrated how lighting and students' learning performance are connected, better lighting leads to an increase in students' learning motivation [41]. Because of these reasons, a hotel room that allows being customized by the guests according to their needs or desires could play an important role in promoting the hotel's revenue.…”