A film leader is a length of film attached to the head or tail of a film to assist in threading a projector or telecine. Leader attached to the beginning of a reel is sometimes known as a head leader, or simply head, and leader attached to the end of a reel known as a tail leader or foot leader, or simply tail or foot.
A universal film leader is a head leader designed for both television and theatrical motion picture exhibition applications. This not only includes the countdown, but technical information about the film, including, but not limited to, title, studio, production number, aspect ratio, sound level and mix, reel number and color.
Head leaders are marked with visual and audio information that may be used to ensure that the correct amount of time is allowed for the machine to run up to speed and arrive at the beginning of the program or movie. They generally feature a countdown.
Two versions of head leader are well-known:
- "Academy Leader". Sometimes called the "Society Leader," and dating from the 1950s, it has numbers marked once every foot (16 frames/foot in 35 mm film), counting down from eleven to three. "NINE" and "SIX" are spelled out, to avoid confusion between 6 and 9 when viewed upside-down. At 3, a quick beep is heard. The Academy leader is specified by SMPTE 301.
- "SMPTE Universal Leader". In the mid-1960s, the Society of Motion Picture and Television Engineers (SMPTE) replaced the Academy Leader with a newer universal leader, called the "SMPTE Universal Leader," designed for both television and theatrical projection applications (though it did not gain widespread acceptance theatrically). It featured a continuous countdown from eight to two (measured in seconds, rather than feet), with the numbers in the center of a target with two white circles and a rotating "clock arm" animation. At the beginning, before the countdown, it features "16 SOUND START" and then "35 SOUND START" in a circle target. Then "PICTURE START" appears and the countdown begins. During the four count, the letters "C C F F" would appear around the countdown, signifying the use of those frames as "control frames." At two, a quick beep would be heard, sometimes known as the 2-pop. The Universal Leader is specified by ANSI/SMPTE 55.
See also 
- SMPTE 301M-1999. SMPTE STANDARD for Motion-Picture Film: Theater Projection Leader, Trailer and Cue Marks. Society of Motion Picture and Television Engineers. White Plains, NY.
- SMPTE 55-2000. SMPTE STANDARD for Motion Picture Film: 35- and 16-mm Television Release Prints -- Leaders and Cue Marks. Society of Motion Picture and Television Engineers. White Plains, NY.