###### Abstract  
The main goal of this paper is to evaluate the effect of color changes on the interior surfaces of a selected hall on the level of daylight, represented by the DF factor. A single-story hall was chosen as the reference building, in which daylight falls through the side windows and a skylight at roof level. Measurement of the level of daylight in the real state of the building (in situ) was carried out. The measurement took place when the external boundary conditions of the measurement were met (external state of the sky). A survey was conducted among users, in which they considered the visual perception of the environment and what colors would be suitable for the walls, ceiling, and floor in the working environment of the hall. The evaluation of the respondents who considered the color of the floor was interesting, and several agreed that the floor should be brown. After debugging the model for the simulation based on the actual state of the measurement, simulation calculations were performed with selected surface colors in the interior of the hall. Computational simulations were performed for changing calculation boundary conditions. Daylight Factors (DF) (%) were evaluated, namely minimum, maximum, and average DF values for 15 selected simulations. The calculations were performed in the RADIANCE simulation program. Simulations included the change in the surface color of the simulated wall and the current ceiling surface color, the color of the simulated ceiling surface and the current wall surface color, and the color of the simulated wall and ceiling at the same time. The floor color did not change during the evaluation; it was considered brown. Based on the evaluation of AHP, evaluations of the significance and comparability of colored areas were performed. The value of the average DF was chosen as the most important, the less significant minimum DF value was chosen, and the maximum DF value was  
productivity of employees in the work environment. It is known to have a positive effect on human health as well as on performance and productivity [14; 15; 16]. Daylight is an important requirement for improving comfort in an industrial environment [17]. The industrial and labor sectors consume large amounts of energy for daily production activities. It is also necessary to pay attention to the design of industrial construction. It brings new meaning and wealth to architecture. It allows architects to economically justify other visual elements that enrich the overall design [18; 19; 20]. Buildings that provide a high level of natural light generally have a more positive work environment than those that depend on artificial light. Humans are known to respond better to natural light conditions as their eyes and brains function better, leading to improved concentration and overall performance [21; 22; 23]. The introduction of skylights reduces dependence on artificial lighting and significantly reduces energy consumption and operating costs, as well as positively affects the overall carbon footprint of buildings [24; 25; 26]. In the case of large buildings, it is possible to use light pipes instead of artificial lighting [27; 28]. Color is an essential element of interior design and influences the subjective visual perception of light. Color is associated with psychological, physiological, and social reactions. A color solution for a particular space may depend on several factors (type of activities, nature of light sources, size and shape of the space, etc.). Color also helps people interpret and understand the physical environment [29]. A study [30] showed that electricity savings of up to 45% could be achieved by increasing the reflective properties of surfaces. According to [31], it was found that within reasonable limits, wall albedo changes have little effect on the daylight factor. The study [32] analyzed the relationship between surface color reflectance and lighting efficiency. This study found that the reflectiveness of the ceiling affects the performance of lighting systems.