## 4 Discussion
### Strengths and Limitations of This Study  
This study focused on dual-tone architectural color combinations, exploring differences in perceptual quality under various combinations by examining the relationships between color element differences, eye-tracking metrics, and subjective evaluations. Current architectural color experiments often emphasize single colors, which diverge from the reality of residential color schemes in China. By focusing on dual-tone architectural colors, this study breaks away from the limitations of previous research on color experimental samples. Through regression analysis, we precisely delineated and explained the specific impact levels of color element differences, providing accurate data support for research on dual-tone architectural color combinations. Previous architectural color studies often used open-ended scales to gather subjective evaluations from participants. However, subjective expressions of color preferences can be influenced by factors such as individual education, geographic location, and cultural background [6], leading to inconsistencies between physiological responses and subjective evaluations. This study introduced eye-tracking as a physiological indicator to bypass the subjective processing of color perception, directly collecting users' visual feedback on color stimuli to validate subjective evaluations. The aim was to enhance the accuracy and representativeness of experimental data. It should be acknowledged that, although eye-tracking experiments have improved the accuracy of color perception to some extent, human visual perception and subjective preferences cannot be fully captured through a single eye-tracking technique [15]. Future research should incorporate a broader range of physiological indicators, such as EEG, skin conductance, and blood oxygen levels, to conduct a more comprehensive quantitative analysis of color perception. Additionally, this study preliminarily validated that eye-tracking metrics can serve as evaluation indicators for measuring color visual quality. However, relying on a single experiment may not accurately capture individual preferences. Previous eye-tracking studies have shown that FC and FFD can reflect participants' preferences to some extent regarding experimental stimuli [46; 67]. Despite this, color combinations with excessive \(\Delta\)h and \(\Delta\)L tend to elicit heightened physiological attention [38; 68], which is not necessarily driven by preference [65]. Therefore, future eye-tracking experiments in the field of color should focus on identifying the specific causes behind eye movement indicators. Comprehensive data metrics are crucial for color-related visual quality studies to fully understand individual visual experiences. During the experiment, the focus was on investigating the relationship between color combinations and visual quality, so only architectural units were selected as the experimental subjects. Factors such as the surrounding ancillary buildings, community environment, sky view factor, and green view index were not considered in evaluating the visual quality of individual buildings. In future research on the overall community environment, it will be necessary to adopt a more comprehensive approach, considering various influencing factors to assess their impact on the visual quality of architectural color combinations. This experiment also has certain regional limitations. The architectural styles used as subjects were based on a survey of old residential buildings in the Shanghai area. It is undeniable that the architectural forms of old residential buildings vary across different regions of China. Therefore, the generalizability of the experimental conclusions requires further validation through color studies conducted in other regions. Additionally, the extent to which cultural background influences individual color perception remains under-researched and lacks quantifiable studies.