How to affect the quality of the light
Is the light is giving you the look you desire? By themselves some light sources are very hard, creating very dark and crisp shadows. To soften the light you need to diffuse it by adding modifiers: an umbrella, a softbox, or even a fabric screen. Think about how you would soften the light coming through a window, that is the look you want to achieve.
Get the light close to the subject without it being in your frame. Having the light closer to your subject creates a better quality of light and shadow. Setting the light too far back makes it dull.
Adjust the angle based on how you want the shadows to fall. If you want to add more dramatic shadows, then angle your light more. To achieve even light, bring your light almost directly in front of the subject. Adding a reflector on the other side will reduce the contrast and open up the shadows, if you prefer.
How do you achieve a similar look with artificial light as you do with natural light?
If you are seeking a soft and diffused light, like on a cloudy day, use a large softbox fairly close to the subject and slightly angled toward them. This creates less shadow. Remember, the larger your light source, the softer the light.
Rim light adds drama and separation around the edges of your subjects. To accomplish this with artificial light place the subjects with their backs to the light, and use a another light in front at a lower setting to light the faces. If you are using a small off camera flash to achieve this then the light from behind may be too harsh. If you diffuse that light then it becomes softer and wraps more around the subject. Colored gels are available to give the light a color tone.
The look of widow light can be achieved with a large softbox. Make sure you angle the softbox slightly away from the subject so that you are feathering the light just as you would by a window.
Tushna Lehman is an acclaimed designer who has gone back to her first love, photography. Her studio, T-elle Photography has evolved into a successful lifestyle and portrait photography studio serving the greater Seattle area. She also offers boudoir photography to her clients.