And the right color pen. God forbid you fill in an official form in the wrong color pen.
Certainly an interesting man. I highly recommend checking some of his work (ie. The Metamorphosis).
For more information, you can check whether the ink complies with DIN ISO 12757-2 and/or read up on "Dokumentenechtheit" [1]
[1] https://de.wikipedia.org/wiki/Dokumentenechtheit (It hasn't been translated to other languages yet.)