Synchronisers: Types and Uses

Like motorised editing machines, synchronisers are vital pieces of cutting room equipment. The synchroniser, which is sometimes called the gang synchroniser, is a device for keeping the picture and a number of soundtracks in synchronism on the cutting bench.

The bench is easy to identify because it will normally have two linen bags hanging underneath. Between the two bags is a square glass panel set into the surface of the bench. A light is positioned under the glass panel and the synchroniser is normally used on this panel so that light shines through the film. The top of editing benches should be covered with plastic laminate or something as tough and easy to keep clean. It should not be longer than 60in and about 24in deep. It is a good idea to have either a film cuts rack (see list of accessories) or racks for holding small reels of film trims behind the editing bench. On the top of the bench, as well as the synchroniser you will always find at least one rewind arm and possibly a film horse but the central and most important piece of equipment will always be a synchroniser.

Gang synchronisers

A synchroniser has two or more sprockets locked on a common shaft which holds picture and sound in perfect synchronism, even when moved. The film is held on the sprockets by sprung rollers which can be raised to place the film on the sprocket teeth, then lowered and locked to hold it in position. Once the film is locked on the sprocket teeth it will remain synchronised which ever way the sprockets turn. The main shaft turns on sealed ball-bearings and synchronisers generally need little maintenance though they must be kept clean at all times. Like the editing machine, there are several different models to choose from. The two main kinds of synchroniser are the standard type and picture synchronisers. Both types are available in a number of different models.

Synchronisers are available in 16mm two-way and four-way models, and combination 16mm/35mm synchronisers are also quite common, The fpur-way synchroniser (also known as the four gang synchroniser) has four separate sprockets locked to a common shaft and the two-way has, naturally, two. The four-way is widely used when preparing soundtracks and for negative cutting.

1. On the left of the bench a film horse (A) holds film on cores. Synchroniser (B) and amplifier (E) are used throughout cutting. Reels of spacing (D) will also be needed. Cloth bags (F) enable film to be wound back and forth through the synchroniser without using take up (C) until adjustments have been completed.