## 4 Conclusions  
The article deals with the daylight factor DF as one of the basic factors designed to assess the level of daylight in artificial material space. A single-story hall with a side window and a skylight at the top was chosen as the reference building. Activities were performed, namely, the measurement of the level of daylight in the real state of the building (in situ) when meeting the external boundary conditions of the measurement (reference state of the sky). A survey was also conducted among 57 users who considered the importance of the color of the surrounding surfaces in the visual perception of the working environment. They also answered questions such as what colors they consider suitable for the color solution of the surrounding surfaces of the work environment (walls, ceilings, floors). Interestingly, the results indicated that the greatest impact would be the color of the floor, then the walls, and finally the ceiling. In terms of color, the most suitable would be a brown floor, light gray walls, and white ceilings. After debugging the model for simulation with selected real colors of the surfaces in the interior in situ, the boundary conditions of the walls and ceiling were chosen for the considered simulations. These conditions meant changes in color solution, that is, changes in light reflection factors. The floor color was considered brown with a reflectance of 0.2. This means that the floor color was constant throughout the simulation calculation, as chosen by the users. The simulations evaluated the daylight factors (%), namely the minimum, maximum, and average DF. A total of 15 simulations were performed, which were solved by the RADIANCE simulation tool. In each of them, a calculation (as well as a specific measurement in the interior real state) was performed for 60 points (5 times 12 lines). Figure 10: Daylight factor DF (%) in the hall with different surface colors (various reflectance). The main motivation for this study was to determine the impact of different colors of the surrounding surfaces on the work environment. The simulations included changing the simulated wall surface color and the current ceiling surface color, the simulated ceiling surface color and the current wall surface color, and the simulated wall and ceiling surface color at the same time. The floor color remained unchanged. Standard lighting regulations affect human activity and the quality of work. In our conditions, it is normally 500 lx during normal work activities. According to the SK national standard, in terms of limited measurement accuracy, daylight is considered satisfactory if the results of measurements or simulations do not differ from the required values by more than 15%. This fact is not fulfilled. The calculated values document the fact that:  
i DF\({}_{\text{min}}\) is unsatisfactory in functionally defined parts of the space because the condition is not met. DF\({}_{\text{min}}\) is 0.2-0.7, which is less than the required level of 1.5-2.0%. ii Average DF assumes a share of ceiling lighting in the average value of DF of more than 5.0%; The calculated value of 3.1-4.8% is suitable for lighting-class IV. iii The uniformity of daylight (U0) in the space of the combined lighting (windows, skylights) is met if the minimum and average value of DF is met. The uniformity of the lighting, in this case, is not satisfactory for lighting-class III or IV. When performing the activity, it will be necessary to supplement the daylight with artificial lighting in the place where the work activity will be performed. As mentioned, 15 computational simulations were performed in this work based on the AHP evaluation. Classifications of the significance and comparability of color areas were performed. The results show that the simulated alternatives sim10 (walls and ceiling light gray), sim7 (walls bright yellow and ceiling white), and sim6 (walls traffic yellow and ceiling white) are suitable for the color of the surrounding areas of the working environment.