In studio portrait photography you will be using only artificial lighting.  This allows you to manipulate the lighting to your best advantage so as to produce exactly the effect you want – soft portraits, dramatic brightly lit images, or side profile portraits.  Here are some tips that can help you with lighting in studio portrait photographs.
 

Butterfly lighting

This is the most basic, traditional form of studio portrait photography lighting and is also called paramount lighting.  It basically uses two lights, the key light which is placed directly in front and higher than the subject’s face and another light called the fill light which is placed below the key light at the height of the subject’s head.  A reflector should be used on the opposite side.  Together these lights light the shadows on the face creating a butterfly effect.  In addition, you could also use a hair light opposite the key light and a background light low and behind the subject.
    

Loop lighting

This is a variation of the butterfly lighting in which the key light is lowered and moved to the side of the subject’s face.  The fill light is placed on the opposite side.  You need to be careful that the fill light does not cast a shadow in the field.  If you are using the hair and background lights, they would be in the same position as for butterfly lighting.
    

Rembrandt lighting  

As the name suggests, this is inspired by Rembrandt who used skylights in a pattern to illuminate his subjects.  In this form of studio portrait photography lighting, the key light is moved lower and more to the side to light the subject’s side face.  The fill, hair and background lights are used as in loop lighting.  In addition, Rembrandt lighting uses kicker lights to light up the shadowed side of the subject’s face.  This creates a brightly lit, dramatic portrait.  Take care to ensure that the kicker light does not shine onto the camera directly.
    

Split lighting 

In this form of lighting, the key light only illuminates one half of the subject’s face.  Place the key light to the side of the subject’s face or even slightly behind.  The fill, hair and background lights are used as in loop lighting.  This too creates dramatic portraits and can be used to make the face look slimmer or hide irregularities in the subject’s face as one half of the face is in the shade.

Rim lighting 

This is also called profile lighting.  In this form, the subject’s face is turned 90 degrees from the camera lens.  The key light is placed behind the subject and illuminates the side profile, outlining the edge of the face as well as highlighting the neck and hair.  The fill light is placed on the same side as the key light so you need to use a reflector to fill in shadows.  Hair and background lights are optional in this form of lighting.