Procedure: First, cut and hem muslin to fit your window. Next, paint your ghost or other shape onto muslin. Stacy used Adobe Illustrator software to print her design on paper in tile mode, traced her design onto her curtain with a Sharpie, and then filled it in with paint. I free-handed my designs directly onto my curtains with black paint.
After your designs are completely dry, cut and hem the chiffon to fit your window and sew it to the muslin, layering it so that the chiffon goes over the painted side of your muslin. Attach your project to a curtain rod in any way you choose (you could use clips; I sewed tie-ribbons to mine; Stacy sewed a rod pocket into hers). Hang with the chiffon side facing out for a great spooky display your neighbors can see and appreciate.