Batman's cowl is one of the more distinctive masks worn by the many comic book super heroes we've grown to love. His distinctive cape and cowl would find a happy home in the closet of any fans of the caped crusader, and it's even possible to make your own. You won't need your own bat cave to assemble a Batman cowl, but it is a rather difficult costume to make, so ensure your skills are up to the task.
Design and cut the fabric to be used for the cape. Batman's cape and cowl are usually black or dark blue, but you can use any color you'd like. At the top of the cape will need to be a means of securing it to your body. Gluing on a button snap to secure the cape under your chin will work, or you can also sew the cape right to the shoulders of your shirt or garment to be used on your costume.
Cut and shape the fabric for the hood. It is incredibly helpful to have a Styrofoam model head to help cut the fabric for the mask and to use a fabric with some elasticity. Pull the hooded fabric tight over the head and run a seam down the back of the mask to keep it tight. Remember that this mask will need to be tight enough to stay secure over your face, but not so tight that it is impossible to get on or off. Make sure to leave the hood long in the back so it can be sewn to the cape.
Measure and cut the holes for the lower jaw and eyes carefully. The eyes are simpler, so do those first. Use a tiny blade to carefully cut the holes for the eyes and remember that they shouldn't be too big. The mouth is trickier. Note that the Batman cowl's does not cover his mouth or chin at all, as the mask stops just past his nose and leaves a wide hole all the way down past his chin. This is a tricky cut, so it may help to be wearing the mask and have someone draw the shape of your face on the uncut hood to give you a guide to follow.
Attach the mask to the cape. Sewing the mask to the cape isn't especially difficult, but there are some things to consider. By keeping the mask long in the back, you give it some slack to ensure you don't rip the stitching out when you turn your head suddenly. For that reason, you should also sew the mask to the underside of the cape to hide the stitching and the extra slack.
Give the mask bat ears and defining features to complete it. The ears can be sculpted from clay, rubber, latex or whatever you have on hand, provided they are symmetrical. Either paint them or cover them in the same fabric as the mask and cape to match and carefully glue or sew them onto the mask. With the ears affixed, there are a number of other little tasks to give the mask more personality. Glue thick, beaded yarn above the eyes to give it a distinctive brow, and another down the nose to give it a point. Also, cut shallow semi circles from the bottom of the cape to give it a ribbed, wing-like look.
Since there have been so many different designs and costumes worn by Batman, you can base the color and detailing after your favorite version.
Only professional costume makers or people with lots of experience should ever attempt to cut a mask while someone is wearing it. It is very dangerous, so do not attempt unless you are a professional.