C'mon peeps. I'm not the only one who read that & .
... back to your situation. I'm perplexed with the 6-inch long scratch. Opening a car door normally would lead to a dint unless the car was moving. Could it be your car was keyed?
it's verticle, and very much a paint on door scratch. I've put some effort into buffing it out. I think its length might be an indicator of how hard the knock was. I'd post a pic but still haven't bothered setting up a photobucket replacement.