The basic purpose of lighting is to bring out the subject to make it visible in a photograph. But for the advanced photographers who are simply tired of flatly lighted portraits, lighting is a process of setting up the lights to impart personality and character to a portrait and fill it with emotion. Unknown to many, dramatic lighting can be achieved with just a single light source strategically placed to a location where it can create high contrast shadows on the face of a subject. Before we venture into this discussion, we should first familiarize ourselves with the basic lighting set-up composed of three lights: the key or main light, the fill light and the back light. Since I am using Nikon speedlights, SB800 and SB600, in my sample photos, I will limit my discussion on lighting techniques with these speedlights as my light sources.
The key light is the strongest light usually placed on a high angle and on the side of the subject. It is mostly mounted on a reflective umbrella directed towards the face of the subject. The fill light or the weaker light can be provided by a light source mounted on a shoot through umbrella or if dispensed with, can be sourced from a reflector or from an existing natural light. The back light separates your subject from the background to create an edge light on your subject.
Going back to our topic on dramatic light set-ups, a single light source may just be enough to light your subject if you know how to set it up in such a way that your light direction will properly hit your subject's facial contours to give it an outline of shadows and highlights. In my first sample portrait above, the light source was placed on the left side at angle in front of the subject to create shadows on the right side of the model's face.
The second photo from above was lighted by a key light placed on the right side slightly at the back of the model while the third photo was lighted by exactly the same set up but this time the model was instructed to move a little bit backwards. The light provided by the key light perfectly illuminated the facial countours and since it was placed at the back of the model, it serves as a backlight too and created some edge light on the head and shoulder of the model. 
The fourth sample photo was lighted by two light sources and they were set-up to achieve a Rembrandt effect. The Rembrandt effect is a high contrast lighting scheme and is achieved by placing the key light at a high angle to your subject's face. The Rembrandt effect is characterized by a triangular light underneath the subject's eye. It also allows the nose shadow to blend in with the shadow on the dark side of the face.
The last two photos were shot on an indoor location and ligthing the subject with a light source mounted on board a camera would not achieve the same effect so using two light sources placed away from the camera will do the job. On the fifth sample photo from above, the model was asked to posed on a hallway corridor. The key light was placed on the right side and in front of the model while the fill light/backlight was placed on the right side at the back of the model. On the last photo on the stairway, the key light was placed at a high angle on the left side of the model while the fill light was pointing directly towards the face and was placed on the ground.For modelling credits, I would like to thank Klaudia Batzler, a Filipina-German who gamely followed my instructions. Make-up services was provided by Pam Dionisio.
