EFFECTS OF BACKGROUND COLOUR ON VISUAL FATIGUE FROM READING ON TABLET

Abstract

This study aimed to investigate the effect of visual fatigue from reading on a tablet when the background luminance and colour were changed. Six levels of background luminance were tested. They were the level with the same luminance as paper (68 cd/m2), three levels with 15%, 30% and 70% increased, and two levels with 15% and 30% decreased from the paper luminance under the same lighting condition. Six background colours with the same luminance as paper were tested: white, red, green, blue, yellow and purple. Subjects read pseudo-text containing 10 lines per page. There were two types of pseudo-text: Thai and English; each had 3 pages. The time subjects spent finding the target letters that were randomly inserted in the pseudo-text was recorded. After the reading tasks, subjects rated the degrees of visual fatigue symptoms that possibly occurred during the tasks. They also answered the general questionnaire about the familiarity of using a tablet and colour preference. Fifty university students with 18 – 35 years of age took part in the experiments. The results showed that the main factor that affected visual fatigue was luminance. Reading media did not affect visual fatigue when the luminance was equal. The level of luminance that tended to cause visual fatigue was +70% from the paper luminance. Colour did not affect visual fatigue. Nevertheless, there was a tendency that red background was the most suitable for reading.