HISTORY | FOG IN UK FILM STUDIOS CLEAR FOR ACTION In the early days of cinema, the UKs biggest studios were in central London, but pervasive fog pea-soupers was entering film sets and causing huge disruption. Richard Farmer describes how pioneering air cleaning techniques saved the studios A scene from Sailors Dont Care at the Gaumont-British studios in Londons Shepherds Bush in 1928 F ilm studios were developed in the early decades of the 20th century, in part to offer shoots a degree of protection from the vagaries of the weather. British film-makers, however, found that studio-based production was not a solution to all their weather-related problems. Located, for the most part, in London, the British film-production sector had to contend with that citys most notable meteorological occurrence: fog. The heavy, industrial-era fogs of the Victorian period known as pea soupers or London particulars formed when moisture in supersaturated air (for example, mist) condensed on particles of largely man-made smoke, and persisted well into the 20th century. They were most problematic during the winter fog season, which lasted from November to March. Film producers found that fog worked its way inside the studio, where it disrupted shooting. Even a light fog was visible to the camera more so than to the human eye and it was not unusual to lose whole days of filming, and significant amounts of money, to fog. A solution needed to be found if the industry was to remain operational all year round and compete with films made in other countries. Some producers decamped to warmer, clearer climes in the winter, with the French Riviera proving particularly popular. As one director grumbled in 1922, Britains winter climate meant that, for months each year, British pictures can be produced abroad better than they can be in Britain. Technological solutions were sought that would permit production to continue closer to home. Heating the stages reduced the relative humidity of the air and prevented water vapour condensing into fog. It also had the effect of evaporating fog that entered the studio from outside. The Whitehall studios, at Elstree, boasted an underfloor heating system 90 pipes of 2in (50mm) diameter which prevented fog from interrupting filming. Together with the heat given off by powerful electric lights, this could make studios extremely hot, and when Chu Chin Chow (1934) was made at Islington, some technicians worked in a state of near undress. Londons industrial fogs also contained particles of pollution, however, that remained in the air even after the water had evaporated. These were visible to the camera, so studios were compelled to clean the air that entered, and then circulated around, their production spaces. Various solutions were proposed, including pressurising the studio environment to prevent fog ingress, and using a direct current brush discharge ioniser to bring down soot particles. This latter idea was never implemented, probably because, as one trade paper noted, such equipment was not altogether without effect upon human beings Drowsiness and nervous symptoms are believed to be sometimes brought on by it. More effective, and safer, were air conditioning systems, the first of which was installed at the Famous Players-Lasky studios in Islington a location described as the very worst position for fog in the whole of London. When the studio opened in the spring of 1920, high- and low-pressure coils were installed on opposite walls of the stages to move foggy air towards the roof, where it was expelled by an exhaust fan. Initial tests found that, even when the fog could not be dispersed entirely, it could be raised to a height of 15 feet (4.5m) above the floor, allowing production to continue underneath. The system proved unable to cope with heavy fogs, though, and 20 days were lost during the studios first year. Consequently, a new system was installed. Designed by W E Riley who, as London County Councils chief architect, had helped design the London Undergrounds ventilation plant and S L Groom, of the Carrier air conditioning company, the system consisted of an air washer that circulated up to 3.5 million cubic feet of air per hour (27.5 m3s-1). It drew air from 42 March 2022 www.cibsejournal.com CIBSE March 22 pp42-44 Film Studio Fog.indd 42 25/02/2022 16:57