These data-sets contain information relative to the Paper entitled “Light and Perception: Study of the Effects of Daylight and Artificial Light on Affect, Mood and Sleepiness under a Sky-Lighting Machine” Please request access to the dataset by email (ffavero@kth.se) stating the reason for the request and the way the dataset is intended to be used. The data-set contains relevant perceived health symptoms data divided by participant ID (N = 28) and session number (N=9), summarised by Task (Game) and Light Condition (Daylight DL; Artificial Light AL). The data-set contains Affect, Sleepiness and Mood data divided by participant ID (N = 28) and session number (N=9), summarised by Task (Reading and Game) and Light Condition (Daylight DL; Artificial Light AL). We coded AL as 0 and DL as 1; Reading as 0 and Game as 1. The data-set includes factors Gender, Order and Time of Day. Plus these subjective parameters, used as predictors in the models: perceived Color of Light and perceived Level of Light (Brightness). These photometric values were included as predictors in the model: Mean Illuminance, referred to as Room Illuminance; Mean Correlated Color Temperature (CCT); Variation, defined as the Standard Deviation (SD) of the Illuminance values; mEDI means calculated with CIE S 026/E:2018 on the spectral values of the two median Illuminance measurements taken over the time-span of thirty minutes; Illuminance measured by the actigraphs, referred to as Personal Illuminance. Personal Illuminance values were asymmetrically distributed and were logged. The file Light-Perception_Exposure-DL-Data-set includes photometric measurements each 30 minutes during Daylight sessions.