ratios (most commonly 1.85:1) used in modern feature films makes inefficient use of the available image area on 35 mm film using the standard 4-perf pulldown; the height of a 1.85:1 frame occupying only 65% of the distance between the frames. It is clear, therefore, that a change to a 3-perf pulldown would allow for a 25% reduction in film consumption whilst still accommodating the full 1.85:1 frame. Ever since the introduction of these widescreen formats in the 1950s various film directors and cinematographers have argued in favour of the industry making such a change. The Canadian cinematographer Miklos Lente invented and patented a three-perforation pull down system which he called "Trilent 35" in 1975 though he was unable to persuade the industry to adopt it. The idea was later taken up by the Swedish film-maker Rune Ericson who was a strong advocate for the 3-perf system. Ericson shot his 51st feature Pirates of the Lake in 1986 using two Panaflex cameras modified to 3-perf pulldown and suggested that the industry could change over completely over the course of ten-years. However, the movie industry did not make the change mainly because it would have required the modification of the thousands of existing 35 mm projectors in movie theaters all over the world. Whilst it would have been possible to shoot in 3-perf and then convert to standard 4-perf for release prints the extra complications this would cause and the additional optical printing stage required made this an unattractive option at the time for most film makers. However, in television production, where compatibility with an installed base of 35 mm film projectors is unnecessary, the 3-perf format is sometimes used, giving—if used with Super 35—the 16:9 ratio used by HDTV and reducing film usage by 25 percent. Because of 3-perf's incompatibility with standard 4-perf equipment, it can utilize the whole negative area between the perforations (Super 35 mm film) without worrying about compatibility with existing equipment; the Super 35 image area includes what would be the soundtrack area in a standard print. All 3-perf negatives require optical or digital conversion to standard 4-perf if a film print is desired, though 3-perf can easily be transferred to video with little to no difficulty by modern telecine or film scanners. With digital intermediate now a standard process for feature film post-production, 3-perf is becoming increasingly popular for feature film productions which would otherwise