correction.
You typed 'so e, what you are saying is that has an inverse relationship with price. price trending up, black line turned down. what happens if the line is flat (not up or down)??'
No, not at all.ADX moves up when price either moves up or down.
Elder writes,'The Directional system (ADX) identifies trends and shows when a trend (bullish or bearish) is moving fast enough to make it worth following. It helps traders take chunks of profit out of the middle of important trends'
I added the info inside the parentheses.
(The letters ADXwere removed by spelling/typo checker.)