I saw the movie Avatar in 3D a few weeks ago. The visuals were literally amazing; I felt that I was witnessing a historical benchmark in film presentation. Part of what made it so excellent and life-like was the lighting. Lighting has always been a huge part of filmmaking, especially a century ago when artificial lighting was considered a special effect.
Movies made in the late 1890s and the early 1900s didn't really use any artificial lighting, instead relying on sunny cloudless skies to light their work. It's ironic, because there were techniques used in still photography that would have worked well with movies; I guess no one considered using them with moving photography. Studios were often on rooftops or used open ceilings to maximize the number of hours of sunlight. The availability of sunlight has been cited as one of the reasons our film industry moved out of New York and in to California.
Early artificial lighting in movies was accomplished using arc lights and mercury vapor light bulbs
(early versions of technology still used today). The light from arc lights derived from an electric spark hopping around two carbon poles. Mercury vapor lights worked like fluorescent tubes
work today. As more and more filmmakers adopted these artificial lighting methods, it became clear that new methods were needed. Experiments began indoors and out to find new lighting sources.
Enter incandescent light bulbs. Relatively primitive, these predecessors to the ubiquitous modern light bulb were far more efficient and easy to manage than arc lights or mercury vapor lights. Myriad lighting effects were developed such as soft lighting, diffusion, high contrast, etc. Filmmakers were excited about these developments and quickly took advantage of the effects.
Nearly a century later the term "artificial lighting" means something totally different. Now it refers to computer-generated light, something ye olde directors could have never even conceived of. The constant development and research of new lighting techniques never ends. It's exciting to think about what kind of amazing things filmmakers will throw at our eyes in the future.