Austrian and Braile Curtains are generally used as Front Curtains (aka Main or Act Curtains), when theatre personnel would like to fly the Main Curtain but have little or no loft space. 

When a traditional backdrop or curtain is flown into the loft, an amount of loft space in excess of the height of the curtain (plus the batten or whatever it is hung on) is required.  For example, a curtain that is 20 feet high might require at least 21 or 22 feet of loft space, or even more, depending on the sight line of the audience.  In the case of an Austrian or Braille, however, the drape gathers upon itself as it opens, requiring little space in the loft – when in the full open (raised) position, it can easily be hidden behind a proscenium or border, taking up very little loft space.

Through the use of a series of lift lines on the back of the curtain, the Austrian or Braille is raised and lowered, with the bottom of the curtain drawing up against itself as it makes its way to the top.  This is similar to the Contour Curtain.  However, in the case of the Contour Curtain, differing amounts of lift are used on the liftlines, giving the curtain the contoured effect.  With an Austrian, equal amounts of lift are given to all of the lift lines, so that the entire curtain raises and lowers in a smooth, fast, and even fashion.

What is the difference between an Austrian and a Braille?  Both use the same lift line system, and both raise and lower in the same manner.  The difference is in the fullness and how the drape appears in the lowered (closed) position.  When down, a Braille Curtain resembles a regular curtain with fullness (similar to a pleated traveller curtain).  An Austrian, however, has additional horizontal fullness created by gathering the fabric along the vertical seams, creating a series of swags even when the drape is in the lowered position. 

Typical fabric choices include theatrical satin and silky chiffon.  Austrian and Braille Curtains required motorized rigging systems to allow the liftlines to be raised and lowered simultaneously in a quick and smooth fashion.