Chroma Key
Lighting conditions have to be more or less perfect with Chroma Key, since any shadows or difference between light levels in any one shot might not register properly with the camera, and cause unexpected results when it comes to keying.
Chropma Key Solutions
This means that the lighting needs to be completely even, since it's best to have as narrow a colour range as possible being replaced. ProAV offers solutions to your Chroma Key issues.