2/5/2025 | 11:00 AM - 12:20 PM | Grand Peninsula A

Improving image equity: Representing the diversity of skin tones in photographic test charts for digital camera characterization

Author(s)

Megan Borek | Imatest

Abstract

Accurate representation of diverse skin tones in photography has been a longstanding challenge due to biases toward lighter skin in traditional reference materials used for film and digital photography, such as Kodak’s “Shirley” cards and the Fitzpatrick scale. These and other tools, such as the ColorChecker Classic, have offered limited ranges of skin tones and do not capture the full diversity of human skin, including variations in shades, undertones, and exposure behavior. In this study, we evaluate the application of the 10-point Monk Skin Tone Scale, developed by Harvard’s Dr. Ellis Monk, to camera testing and characterization using printed skin tone charts. The Monk scale is tested in multiple configurations, including uniform and gradient patches, as well as in color-matched printed faces for testing cameras with facial detection capabilities. We compare the reference CIE LAB values and reflectance spectra of these printed targets to those of other commonly used skin tone references, and to real human skin data. Additionally, we assess the performance of these printed targets in mixed scenes containing both the charts and human subjects, analyzing differences in exposure, white balance, and color saturation. This research identifies limitations and strengths of current printed skin tone scales and charts in representing actual human skin tones, and provides recommendations for improving equitable camera calibration and characterization protocols.