On shoot
- Use the inverse square law.
1. Use the inverse square law.
If you have your subject well lit with one light, and the background is far away, it will receive less light because of the distance. Increase the distance and it will become darker. Of course, this is true with each light added.
- Use a dark flag.
This is the most important thing to understand. With this method you can even "kill" natural ambient light, using a bright light close to your subject.
2. Use a dark flag.
The idea here is simply to cast shadows on your background. It can be a grid, a barn door, or a humongous black card that does not spill theprevents light onfrom reaching the background.
- Use a dark background.
3. Use a dark background
A pretty simple idea, nois it not?
Aditional things.
- You can avoid reflections on a white painted small room adding some dark fabric as a wallpaper or curtains.
4. Lower the ambient light on the room
You can avoid reflections on a white painted small room adding some dark fabric as a wallpaper or curtains.
On post process
You could use a color opposite to the skin tone, in this case, green or blue, and just use the red channel.
Just mask the background and darken it.
5. Color complementary colored background
You could use a color opposite to the skin tone, in this case, green or blue, and just use the red channel.
6. Mask it
Just mask the background and darken it.