It is important to start learning artificial light with a single source, as this will allow you to better understand the properties and fundamental behavior of light. Once you have mastered that, though, adding a second light will open up a lot of creative possibilities that simply would not be achievable otherwise. This fantastic video tutorial features an experienced studio photographer sharing four effective two-light setups for working with models.
Coming to you from Nathan Elson, this great video tutorial will show you four effective two-light setups for model photography. If you are new to working with multiple lights, notice how Elson emphasizes the use of a second light as a means of controlling contrast and making the lighting look more natural. Rarely will you use the second light as a second key light; rather, it will allow you to control some parameter independently of the key light, which, in turn, will allow you to push the overall look in a more creative direction. Check out the video above for the full rundown from Elson.
If you would like to continue learning about how to light a portrait, be sure to check out "Illuminating The Face: Lighting for Headshots and Portraits With Peter Hurley!"