rigid television studio production sets. The home movie market gradually switched to the even less expensive 8 mm and Super 8 mm film formats. 16 mm, using light cameras, was extensively used for television production in many countries before portable video cameras appeared. In Britain, the BBC's Ealing-based film department made significant use of 16mm film and, during its peak, employed over 50 film crews. Throughout much of the 1960s-1990s period, these crews made use of cameras such as the Arriflex ST and Eclair NPR in combination with quarter-inch sound recorders, such as the Nagra III. Using these professional tools, film department crews would work on some of the most significant programmes produced by the BBC, including Man Alive, Panorama and Chronicle. Usually made up of five people, these small crews were able to work incredibly efficiently and, even in hostile environments, were able to film an entire programme with a shooting ratio of less than 5:1. Beginning in the 1950s, news organizations and documentarians in the United States frequently shot on portable Auricon and, later, CP-16 cameras that were self-blimped and had the ability to record sound directly on film. The introduction of magnetic striped film further improved sound fidelity. Replacing analog video devices, digital video has made significant inroads in television production use. Nevertheless, 16 mm is still in use in its Super 16 ratio (see below) for productions seeking its specific look. Format standards Perforations Two perforation pitches are available for 16 mm film. One specification, known as "long pitch", has a spacing of and is used primarily for print and reversal film stocks. Negative and intermediate film stocks have perforations spaced , known as "short pitch". These differences allow for the sharpest and smoothest possible image when making prints using a contact printer. Film stocks are available in either 'single-perf' or 'double-perf', meaning the film is perforated on either one or both edges. A perforation for 16 mm film is with a radius curve on all four corners of . Tolerances are ±. Standard 16 mm The picture-taking area of standard 16 mm is , an aspect ratio of 1.37:1, the standard pre-widescreen Academy ratio for 35 mm. The "nominal" picture projection area (per SMPTE RP 20-2003) is 0.380 in by 0.284 in, and the maximum picture projection area (per SMPTE ST 233-2003) is 0.384 in by 0.286 in, each implying an aspect ratio of 1.34:1.