## 1 Introduction  
The Commission internationale de l'eclairage (CIE) [1] has proposed integrative lighting. The term \"human-centric lighting\" (HCL) carries a similar meaning. It specifically integrates both visual and non-visual effects and produces physiological and psychological benefits for people. [PERSON] et al. [2] outlined human-centric lighting that can be designed by manipulating four lighting variables--the light level, light spectrum, spatial pattern, and temporal pattern--in the built environment. Light stimulus is processed in visual and non-visual pathways and affects human visual, circadian, neuroendocrine, and neuro-robenvioral responses. The visual pathway involves a process where light is incident on rods and cones, whereas in the non-visual pathway light is incident on intrinsically photosensitive retinal ganglion cells (ipRSCs) [3; 4; 5]. There are two approaches to quantify the non-visual stimulation of light [6; 7; 8; 9]. The measurement based on the spectral response of the photopgments in the cones, rods, and ipRGC photoreceptors measures the melanopic equivalent daylight illuminance (EDI), while the measurement based on melatonin suppression measures the circadian stimulus (CS). Many groups have worked on standardizing HCL evaluation criteria by considering the melanopic effects of ocular light in human-centric lighting [10; 11; 12; 13]. Numerous attempts have been made to develop light-emitting diode (LED) spectral power distributions (SPDs) for human users in the HCL framework [14; 15]. For LED office lighting, [PERSON] et al. [16] and [PERSON] et al. [17] showed that color perception is related to the degree of acceptance by users, which can be assessed on scales of _acceptable-unacceptable_ or _like-dislike_. The more subjects who judge a light source to be acceptable, the better the color quality is. The color qualities of lighting are characterized by two attributes: the color rendition properties and the color appearance of light sources [18]. The color rendition property of a light source is measured by the general color rendering index (CRI) Ra [19]. The color appearance of a light source is quantified by its correlated color temperature (CCT) [20]. The CRI recommendations are described as the minimum values for workplaces and different types of work. For example, the CRI value for offices should be greater than 80 [20; 21; 22]. The CCT recommendations represent warm color as below 3300 K, intermediate color as between 3300 K and 5300 K, and cold color as above 5300 K [21; 22]. A few studies have been conducted on CCT levels for offices. Among them, [PERSON] [23] and [PERSON] [24] suggested that the appropriate CCT levels for work and study are in the range from 4000 K to 5000 K, while [PERSON] et al. [25] proposed that they should be between 4500 K and 6500 K.  
The CIE has reported that the CRI has several shortcomings for evaluating the color rendition properties of LED lighting [26]. The CRI is a single arithmetic mean value, and this cannot predict the color appearance of an individual object's color. Thus, the CRI is inaccurate and incomplete. There is also an additional limitation that is inherent to color fidelity. Measures of color fidelity only predict the average magnitude of color difference and provide no information about the direction of change. To address the limitations and bring in additional information to evaluate color rendition, the Illuminating Engineering Society of North America (IESNA) and the American National Standards Institute (ANSI) published _ANSI/IES TM-30-15: IES Method for Evaluating Light Source Color Rendition_ in 2015 and then, in 2020, the updated _ANSI/IES TM-30-20_ (commonly referred to as _TM-30_) [27]. Psychophysical studies have shown that LED lights that can increase the relative gamut area in comparison to the reference light source tend to be favored [16; 28]. [PERSON] et al. [16] investigated user preference and acceptance under LED lights that present the ability to saturate or de-saturate different colors in an office environment.