Skin tone has been an active research subject in preferred colour reproduction of photographic images. There is a consistent conclusion that preferred skin colours are different from actual skin colours. However, results about preferred skin colours from different reports are not consistent. To enhance skin colours of photographic images reliably, psychophysical experiments were conducted to determine preferred skin colours for preferred colour reproduction. Inter-observer variation and tolerance of preferred skin colours were analyzed as well.
Huanzhao Zeng, Ronnier Luo, "Colour and Tolerance of Preferred Skin Colours" in Proc. IS&T 18th Color and Imaging Conf., 2010, pp 190 - 195, https://doi.org/10.2352/CIC.2010.18.1.art00033