This is a normal phenomenon of LCD screen. IPhone7, 7plus, 8 and 8plus are all LCD screens, and pure black is not pure black (that is, there are pixels on the screen whenever it is turned off). IPhone X is equipped with an organic light-emitting diode screen, which has better display effect, more beautiful colors and more pure black display. In fact, comparing these two screens, the daily normal use experience is similar, and there is not much difference between color fullness and freshness.