Creating rainbows

I have a lot of satin ribbon scraps and was having trouble keeping them flat (I kept getting wrinkles in them no matter how I rolled them, folded them around a small pillow, etc, etc). I thought I had this brilliant idea by hanging them all on a hanger in color order, but this has turned out not to be the best tool...
For the first couple of days, the hanger looked perfect - like a beautiful rainbow of my colorful ribbons. Now my hanger is sagging in the middle and all of the thicker ribbon has slid to the middle, ruining my pretty rainbow.

I guess I need to try this again with two hangers or come upwith another way to store the ribbon.