>>46399024>>46399157Because it's black you retards, that's one of the most basic rules of coloring, you don't use pure white and pure black (except for rare exceptions like pupils or lighting of the eyes), you take another color and degrade it until it looks close to black, that way it looks more vivid and organic and you can use different blacks without repeating the same tone (or just doing something lame like "black but slightly less black, more dark grey this time").
Just look at Ash's hair, it used to be pure black, but they made it (slightly) more detailed later and now it's dark cyan/blue, sometimes it even looks (dark) green.
Lucas and Dawn had generic dark blue=black hair you could find in characters like Sasuke or Hinata, making the blue more vivid until it looks like legit dark blue (not proxy-black) is something they did for the anime