Yes, your long arm quilter needs a square top and bottom on backing fabric to attach to the frame so the top can be placed squarely--if the backing is "off"(read that a little biased) then puckers are more likely and once washed will not be square. I always rip wideback (at least cross grain, I sometimes will leave the selvage alone so there's not lots of threads hanging off) cause wide back is notorious for not coming off the bolt square. A presenter at Guild showed how I could be off as much as 12"--which if your quilter has to square up, may mean not enough fabric given to him/her.
Oops-read that the backing could be off by a much as 12"---not me!
Last edited by quiltingshorttimer; 08-07-2015 at 09:32 PM.