Registration pin

A registration pin is a device intended to hold a piece of film, paper or other material in place during photographic exposure, copying or drawing.

Registration pins are used in offset printing and cartography, in order to accurately position the different films or plates for multi-color work.

In traditional, hand-drawn animation, the registration pins are often called pegs, and are attached to a peg bar.

Also, in traditional, hand-taped printed circuit board artwork, usually at two or four times actual size. Sometimes on a single transparent base, usually mylar, with Layer 1 being on the front and Layer 2 being on the back, in red and green, respectively, for later "separation" into component parts using a process camera.

In motion picture cameras, the pin(s) hold the film immovable during exposure.

In certain "professional" motion picture cameras and "step" printers, there may be two registration pins: one is called the "big pin" and it is employed for primary (axial and lateral) registration while the other one is called the "little pin" and it is employed for secondary (axial) registration. With the "big pin"/"little pin" concept, it is not required to employ side pressure or other means to guide the film through the intermittent movement with absolute precision as the "big pin" is fully fitting in the perforation (the "little pin" is not fully fitting in width, but is fully fitting in height; this difference accommodates slight changes in the dimensions of the film media due to changes in relative humidity and possibly other factors such as media age).

This system is employed primarily in high-end "professional" cameras in the West. In the East (the former Soviet Union and its former Satellites), a single registration pin, corresponding to the "big pin", is employed along with side pressure.

Additionally, Western "professional" cameras always employ Bell and Howell (BH) pins whereas Eastern "professional" cameras generally employ Kodak Standard (KS) pins, which standard was originally recommended by the Western standards organizations, but was soundly rejected by Western studios and camera equipment manufacturers. Western "professional" cameras provided to the East during World War II's Lend-Lease program were generally converted to KS pins by the receiving country.

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Wikipedia