In the days of colour film photography, one of the stages applied was skin tone matching. When trying to set your printer up you printed a fairly standard picture, and checked the skin tone looked right. For a long time nobody thought to do the test with people who weren't white, so often the skin tones of darker people were off - hence the pictures you got developed were more likely to be accurate if your subjects were white.

https://www.npr.org/2014/11/13/363517842/for-decades-kodak-s...