What do you use to paint body panel gap lines?

[PaPeRo]

Is there a special black marker made for this purpose?

[BPSHADOW]

Is there a special black marker made for this purpose?

Usually just a super fine tipped Sharpie, although I dont see too many people do that anymore.

[Tizer]

I have always used Parma's Detailing pen. It has a fine point on one side and a thick point on the other. Works great, better then a normal sharpie.

Now I use Kyosho micron line tape, 0.4mm wide. ABC hobby also has micro line tape.