You don't want to have the backing too taut. I always check the backing when I have it secured to the table to make sure it had the right tension, I would run my hand over making sure there was no movement. It should not be taut like a drum. If you release the backing when finished pinning, if the backing is too tight, the top will have little bits of puffiness because the backing has returned to it's normal shape. Hope this helps.