Optimising Illuminance and Colour Temperature for Users Performing Screen and Paper Tasks to Enhance Cognitive Performance and Visual Comfort

Abstract

This dissertation investigates how reduced light and correlated colour temperature (CCT) affect cognitive function, visual comfort, and psychological well-being in screen-based work environments. Because they were developed for paper-focused professions, conventional lighting standards sometimes overlook modern components like screen luminance, vertical eye-level illumination, and non-visual circadian effects. A survey of the literature indicates that most studies utilise fixed light settings and examine illuminance or CCT separately. In order to bridge these gaps, 60 volunteers took part in a controlled laboratory experiment in which they completed computer-based and paper-based tasks in four different lighting settings, including two colour temperatures (3000K and 4500K) and two illuminance levels (200 and 400 lux). While tests like proofreading, classification, and numerical matching were used to measure objective performance, validated questionnaires were utilised to measure subjective judgments of comfort, clarity, brightness, and attentiveness. Certain lighting metrics, including spectral power distribution and vertical and horizontal illuminance, were recorded using a Sekonic C-800 meter. The study aimed to determine whether lower, low-illuminance light is detrimental to comfortable working conditions, particularly in environments where screens are commonly used.The study's conclusions are expected to support sustainable, human-centred lighting regulations by elucidating how lighting conditions can enhance comfort and accuracy when paired with an appropriate CCT, and how illuminance and CCT together affect performance, well-being, and cognitive performances. These findings show how important it is to reevaluate conventional lighting guidelines in order to improve user comfort and visual environments in modern workplaces.

Keywords: Correlated Colour Temperature (CCT), illumination, visual comfort, cognitive function, screen-based tasks, indoor light pollution, circadian well-being, lighting perception, digital work environments