The IMPACT of Background on a portrait is enormous; tonal values, the mood, the image itself all are affected by how the image is "framed". It is the context of the piece. The intensity or formality of a piece will change when you choose both the colours of the background and the tone. Brushwork plays a huge role. Traditionally you might choose to frame the face with lighter tones fanning a way from the face and body and slowly integrating other colours. Or you may in fact choose the reverse. An intensely applied Inner coat which can act to frame the face and body then a more diffuse approach to the exterior. This is where the strokes of your brush will impact. An intense background can be created in lighter tones but with fretful brush work. Don't limit yourself to long sweeping fluid strokes. Experiment, play, use your full arm. Allow the background to say something about the subject. What does the direction of the background reveal about character? Don't be afraid to add your "Artistic Comment."
You may decide that you wish to add in other physical elements. How does your subject interact or avoid their environment? The environment still needs a background. I once painted a woman sitting in a library. There she was astride a chair looking at nothing in particular, wilfully ignoring the books. But over her left shoulder was a window- What sky did I paint? And what was I trying to say because of the mood of the sky? Everything you do once you pick up that brush is a choice. What do your choices reveal? What do they conceal? Why are you painting this particular subject? How does your choice of background support those decisions?
*As a side note- I used one Black and White still image as a reference shot.
The image below is exactly the same as the image to the right with the exception of background.
Painting details: Acrylic and Oil on Linen Board- 20 x 24".