The color gray is an unemotional color. As we know, before it’s raining, the dark clouds gather in the sky. What we feel is cold, scared quiet, and stressed. From a color psychology perspective, gray is the transition between black and white. The closer gray gets to black, the more dramatic and mysterious it becomes while the closer it gets to silver or white, the more illuminating and lively it becomes. So you can decide to what gray to use depending on the emotional color of your video.
There are 42 gray gradient color matching schemes for your choice.