On all of these pages I used a very thin ballpoint pen (skb ballpoint pen) which is full of character and, as all things with character, it's not so easy to control. I can create many shades of gray with it and can draw and write in the most impossibly-small handwriting - which helps sometimes to get things off my chest or add some special details that only I will notice. The only issue I have is that the pen gets a bit of a blob of ink on it's tip pretty often and they smudge - but there is certain charm in that too :) And dirty fingers.