This is 1/8" thick (the size I use), and very very dark in colour. I did find one place that still makes clipboards from it, but they're too far from here -- delivery would cost more than material. This stuff is normally smooth on one side, and can also be found smooth on both sides. It is made by adding oils to the mix and then heat treating the works as it is pressed into sheet material. Regular "hardboard" (aka mush-board) lacks the oils, and tends to approach a light blonde colour.

Cheers