Open Access Peer-reviewed

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

B.M.T Shamsul1, C.C. Sia1, Y.G Ng1, K. Karmegan1,

1Department of Environmental and Occupational Health, Universiti Putra Malaysia, Selangor, Malaysia

American Journal of Public Health Research. 2013, 1(7), 159-165. DOI: 10.12691/ajphr-1-7-3
Published online: August 25, 2017


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.


lighting, correlated colour temperatures, visual comfort, alertness level, visual task performance
[1]  Åkerstedt, T., and Gillberg, M., “Subjective and objective sleepiness in the active individual,”.International Journal of Neuroscience, 52(12).29-37.1990.
[2]  Altomonte, S. (n.d.), “Lighting and Physiology: Artificial and natural lighting and its relation to human body,” [Online]. Available: http:// [Accessed Oct. 15.2011].
[3]  Barkmann, C., Wessolowski, N., and Schulte-Markwort, M, “Applicability and efficacy of variable light in schools,” Physiology and Behavior, Sept. 2011. doi:10.1016/j.physbeh.2011.09.02.
[4]  Berman, S.M., Fein, G., Jewett, D.L., and Ashford, F, “Landolt C recognition in elderly subjects is affected by scotopic intensity of surround illuminants,” Journal of Illuminating Engineering Society 199, 23(2).1994.
[5]  Boyce, P. R., Veitch, J. A., Newsham, G. R., Myer, M. and Hunter, C, “Lighting quality and office work: A field simulation study (PNNL-14506),” 2003. [Online]. Avaiable: http: // [Accessed Oct.22.2011].
[6]  Chellappa, S. L., Steiner, R., Blattner, P., Oelhafen, P., Götz, T., and Cajochen, C, “Non-visual effects of light on melatonin, alertness and cognitive performance: Can blue-enriched light keep us alert,” 2011. [Online]. Available: http: // [Accessed April. 18.2012].
[7]  Górnicka, G, Lighting at work: Environmental study of direct effects of lighting level and spectrum on psychophysiological variables, Technische Universiteit, Eindhoven, 2008.
[8]  Halonen, L., Tetri, E., and Bhusal, P, Guidebook on energy efficient electric lighting for buildings: Chapter 3: Lighting Quality, Aalto University School of Science and Technology, Finland, 2010, 41-56.
[9]  Hameed, A. and Amjab, S, “Impact of Office Design on Employees’ Productivity: A Case study of Banking Organizations of Abbottabad Pakistan,” Journal of Public Affairs, Administration and Management, 3(1).2009.
[10]  Juslen, H. and Tenner, A. “Mechanisms involved in the enhancing human performance by changing the lighting in the industrial workplace” International Journal of Industrial Ergonomics, 3. 843- 855. 2005.
[11]  Lehrl, S., Gerstmeyer, K., Jacob, J.H., Frieling, H., Henkel, A.W., Meyrer, R., Wiltfang, J., Kornhuber, J., and Bleich, S,“Blue light improves cognitive performance,” Journal Neural Transmission. 114. 457-460.2007.
[12]  Linhart, F. and Scartezzini, J. L, “Evening office lighting – visual comfort vs. energy efficiency vs. performance,” Building and Environment, 46, 981-989. 2011.
[13]  Manav, B, “An experimental study on the appraisal of the visual environment at offices in relation to colour temperature and illuminance,” Building Environment 42, 979-983. 2007.
[14]  Michiko, I., Katsunori, O. and Hiroyasu, U, “Change in Visual Contrast Sensitivity with Age Depends on Illuminance Level,” Journal of the Illuminating Engineering Institute of Japan, 85(5), 352-360. 2001.
[15]  Miller, H. Bright Idea: Personal Control for Office Lighting. Research Summary. 2007. [Online]. Available: [Accessed July, 2011].
[16]  Mills, P. R., Tomkins, S. C., & Schlangen, L. J. (2007). The effect of high correlated colour temperature office lighting on employee wellbeing and work performance. Journal of Circadian Rhythms, 5(1), 2.
[17]  Noguchi, H., and Sakaguchi, T, “Effect of illuminance and color temperature on lowering of physiological activity. Journal of Applied Human Science,” 18.117-123. 1999.
[18]  Park, B. C., Chang, J. H., Kim, Y. S., Jeong, J. W. and Choi, A. S, “A Study on the Subjective Response for Corrected Colour Temperature Conditions in a Specific Space,” Indoor Building Environment, 19(6), 623-637.2010.
[19]  Rautkylä, E., Halonen, L., Lehtovaara, J. (2008). Effects of artificial light spectrum on alertness: Vava – field study. Report 54, Lighting unit, Helsinki University of Technology.
[20]  Sanaz, A.S, “The Influence of Light on Student’s Learning Performance in Learning Environments: A Knowledge Internalization Perspective,” Journal of World Academy of Science, Engineering and Technology, 81. 2011.
[21]  Stephenson, P, “Artificial daylight as ergonomic lighting,” 2005. [Online]. Available: [Accessed Sept.22, 2011].
[22]  Van Bommel, W. J. M. and van den Beld, G. J, “Lighting for work: a review of visual and biological effects,” Lighting Res. Technology, 36(4), 255-269.2004.
[23]  Veitch, J. A. and Newsham, G. R, “Determinants of lighting quality 1: State of science,” Journal of the Illuminating Engineering Society 27(1), 92-106. 1998.
[24]  Viola, A. U., James, L. M., Schlangen, L. J., & Dijk, D. J. (2008). Blue-enriched white light in the workplace improves self-reported alertness, performance and sleep quality. Scandinavian Journal of Work, Environment & Health, 297-306.