Watch this.When you first watch through the commercial, you hardly notice the faces, but on the second run, watch differently. Pause on the clearly seen face shots and identify whether the lighting is hard, soft, motivated, unmotivated, stylistic or natural. It's amazing how a light's color and texture can so tranform the feel of a scene.
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The lighting of a scene is extremely import to the feel of a commercial or any production. Just look at films a little closer. The lighting of faces is the determining factor of how a scene is going to play out. Bad lighting will turn off your audience faster that you could ever imagine.