Here is a rare photo of the "lit" port side of the USS Enterprise eleven-foot studio model. Since the port side of the model had no lights, how was the effect accomplished? Note the "NCC-1701" decal on the port engine nacelle--it's actually a "reversed" decal, which was used on the model so that the port side of the ship could appear to have lights. After filming the ship in this manner, the optical FX houses could reverse the film and have it appear as if the port side of the ship was lit. The photo shown below has been reversed. This FX was used most notably in the episode, "Mirror, Mirror," when the USS Enterprise became the alternate-world ISS Enterprise.