The influence of the Eidophor projection system has been felt for over fifty years, providing users with extreme brightness and unique capabilities in a wide variety of applications. The Eidophor, manufactured by Gretag AG, Switzerland, is an oil layer light valve system invented in 1943 and is still unsurpassed in brightness by any other technology. Although the technology is over 50 years old, there are still many viable uses for the system, particularly in North America. This paper will review the history, technology, applications and outlook for the Eidophor projection system. The applications include permanent locations such as sports arenas and television studios as well as a continuing impact in the large screen display rental community.