Purpose The Fitzpatrick Scale (FS), originally developed to dose photochemotherapy in Caucasian skin, has become widely adopted for skin color categorization. It originally included types I-IV, with types V-VI added later for darker skin. The FS was designed for UV radiation reactivity assessment. However, it is increasingly used as a proxy for objective skin color classification, despite being based on a subjective questionnaire. Individual Typology Angle (ITA), a validated colorimetric measurement, presents a potential alternative. Previous studies examining these classification systems have been limited by small sample sizes and uneven distribution across skin tones with subjects predominantly having lighter skin tones. This study aims to explore these limitations by investigating the relationship between ITA measurements and Fitzpatrick Skin Types (FST) on a self-reported skin color survey in a cohort including the full spectrum of skin tones. Methods This study enrolled 440 subjects to evaluate relationships between subjective skin typing systems and objective colorimetric measurements. Participants completed a questionnaire covering self-reported skin color descriptors (very fair to very dark) and self-assessed Fitzpatrick type (I-VI). Objective colorimetric measurements were taken on the left inner arm using a colorimeter to minimize sun exposure influence. Individual Typology Angle (ITA) values were calculated from the measurements following established protocols. Statistical analysis was performed using pairwise comparisons with t-tests and pooled standard deviations to evaluate the relationships between ITA values and both subjective classification systems (p