Sometimes, when the stripes are printed on especially, the stripes do not line up with the threads in the weave. Then you have to use a ruler like comes for rotary cutting to mark a 90 degree line against the stripe. Then cut it clear across the fabric with the scissors instead of ripping or cutting with the rotary cutter. The line will not necessarily line up with the selvage or the threads in the weave, only with the stripes themselves. Do you know what I am saying?