It is a Screen shot but the print looks the same way. The narrow bar is the bar of a Barbell. It is layered behind the weights on each end and the school logo in the center. I had made a gradient that goes all the way accross the bar which is approx 34" wide and 2" tall, with several color changes accross it's length. That's when I got the banding.
I have found a solution but it doesn't tell me why it happened. I cut the long bar into shorter pieces and made individual gradients instead of one long one. Then it looks nice and smooth.
Fortunately I was able to cut it into sections because it's behind other objects, but if it would have been all visible i don't know what I could have done.
Thanks for your input!