Comparing three iPhone 6s side by side, I noticed fairly significant differences in the appearance of colors between them. One in particular is much warmer looking, especially for whites. I have confirmed that nightshift is off and that no screen accessibility settings are enabled.
I tried to capture the difference in the image below with limited success.
In person, the one on the left is noticeable warmer looking, and the one on the right is redder than the one in the middle (or the middle one is greener than the one on the right).
Could any other setting be effecting the display colors? Or is this color variation just expected for three different devices with different histories?