So yesterday I promised a tutorial on how I do a hidden zipper pillow back. For a 16″ pillow form, you will need: (1) 9″ x 16″ rectangle (1) 12″ x 16″ rectangle (1) zipper 16″ or longer First, take your 12″ x 16″ rectangle. Fold and press 1/2″ along the long side, then press down 1/2″ again. Your piece should now measure 11″ x 16″ Next, fold and press 1″ along the long side of your 9″ x 16″ rectangle, .