All the art for habitat starts with traditional ink and pen, but is colored digitally like so:
Inks
A file i made in 2010 thats a bunch of layered inkwash textures gets dropped on there
A layer mask gets applied to that and i erase and render away where the light falls, to define the shape more
that gets zapped with a brown gradient map and some blues for the shadows
some colors on there
and some extra effects! Done. (there are like a million more microsteps then what is shown here but thats the basic procedure i’ve been using)