I have a scene with a circular plane and three spotlights that shine down on it intermittently. Below is a screenshot of the scene (one of the lights is currently illuminating the plane):
In the final rendering, I only want the circular plane to be illuminated. However, when I render this scene, I instead see some light that appears off the plane. In the image below you can see that light in the lower-right corner of the image:
My question is this: how can I stop the light from appearing in the background of the scene and appear only on the circular plane?