Visual clarity of several learning media under different daylight-opening positions and areas based on students’ performance and perception

Digital display generally uses special lighting that produces different luminance from conventional displays. This study examined the complex effects of varying learning media (whiteboard, glassboard, projector, and smart television [TV]) in various daylight settings — window position (rear and side windows) and opening area (interior window-to-wall ratio [_iWWR] value: 9 %, 47 %, and 85 %) controlled by blackout roller blinds — to produce visual clarity (VCl), which was assessed objectively (accuracy) and subjectively (perception). Based on the optical characteristics, three groups of learning media were created: non-lit devices (whiteboard and glassboard), reflected-lit devices (projector), and self-lit devices (smart TV). The results showed that coordinating daylight settings and learning media can optimise the VCl. A 10 % increase in _iWWR value increases 2 % accuracy and 3 % VCl perception for non-lit but decreases 0.2 % accuracy for luminous learning media (reflected-lit and self-lit devices) — the VCl perception of those devices peaks at a 2 % increase when the curtains are half open. This study proposes a spatial VCl index formed by the sufficient scores of accuracy and perceived clarity across the room. For spatial VCl optimisation on non-lit devices, the side window and 81 % _iWWR were proposed, and 81 % _sVCl was achieved. By contrast, a rear window and a 60–64 % _iWWR are recommended when using luminous learning media, and 91 % _sVCl for reflected- and 100 % _sVCl for self-lit devices were achieved. This study developed practical guidelines by providing white luminance thresholds for media displays, offering adaptable solutions for diverse classroom settings and learning media.