Tong Yu/Getty Images Share on Facebook Share on X Share to Flipboard Send an Email Show additional share options Share on LinkedIn Share on Pinterest Share on Reddit Share on Tumblr Share on Whats App Print the Article Post a Comment The phrase "premium-large format" (or PLF) couldn't sound more technical. But mention Imax - and its winning streak on Wall Street - and all eyes light up. That wasn't always the case. For years, Imax was best known as the giant screen housed in museums that showcased astronauts taking space walks or an African safari in stunning fashion.