With the increased production required by the nickelodeon boom, extra artificial lighting was used more and more in the film studios to supplement diffuse sunlight, and so increase the hours that film could be shot during the day. The main sources used were modified arc lights made for street lighting. These were either hung on battens suspended forward of the actors from the roof, or mounted in groups on floorstands. The addition of a metal reflector round the arc source directed a very broad sweep of light in the desired direction. Large mercury vapour tube lights (Cooper-Hewitts) were also used in racks placed in the same way. Arc lights had been used to produce special lighting effects in films like the light from a lamp or firelight before 1906, but this now became more common.
A strong expressive use of a fire effect occurs in D.W. Griffith'sThe Drunkard's Reformation (1909). Here, the reformed drunkard is happily reunited with his family before the fire in the hearth, in a set-up reproducing that at the beginning of the film in which the fire is out, and the hearth is cold, and the family is destitute.
Low-key lighting (i.e. lighting in which most of the frame is dark) slowly began to be used for sinister scenes, but not in D.W. Griffith films. Vitagraph's thriller, The Mystery of Temple Court (1910) has low-key lighting for a scene of murder, and their Conscience (1912) shows low-key lighting done solely with artificial light for a scene of terror.
This sort of lighting was appearing occasionally in European films by 1911, and in some cases was pushed much further. Lighting from a low angle was used more strongly in the Italian epic film Quo Vadis? in 1912, and then in the famous Cabiria(1914) to reinforce the weird atmosphere in one scene.
Silhouette effects in location scenes began to appear in 1909 in both the United States and Italy; though as things developed, European film-makers made more use of this than the Americans did.
The most important aspect of this was that such shots involved having the sun light the scene from behind, and this approach was extended by using the reflected sunlight from a white surface below the camera to light up the shadow on the actors faces from the front. This is the one novel technique that D.W. Griffith and his cameraman Billy Bitzer may really have invented. The next step was to transfer this kind of back-lighting onto the lighting of actors on studio sets. Up to this point artificial lighting in studio scenes had always been put on from the front or side-front, but in 1912 there began to be a few cases where light was put onto the actors from arc floodlights out of shot behind them and to one side, to give a kind of backlighting. It was not until 1915 that the effect of backlighting of the actors by the sun was fully mimicked in studio lighting, by using a powerful arc spotlight shining from above and behind the set down onto the actors. This slowly became a standard component of the studio lighting of figures in American films, but it took much longer to catch on with European cameramen.
