Hmmm... that might work, but don't you need an image filling the entire screen to do that then? I mean, you need to cover the parts of the screen you don't want lit. Another problem then occurs when you want to use more than 1 light... the lights (images) will cover (and thus darken) each other.

An example of the thing we want to do is to create a dark cave with the player holding a flashlight that lights the area in front of the player and (if possible) multiple (red-colored) lights on the walls for the torches. The rest of the cave (that isn't lit by one of the lights) should be completely dark. How can we create the effect that in the area of the flashlight, the images on the screen have their normal colors and the rest of the area (except the parts with the torchlights) dark.... all of this using alpha gradients for he light's edges, as you said

I think I was wrong when I said lighting in the first message ops: The thing we actually want here is darkening rather than lighting, because we want to darken the unlit parts and leave the lit parts as is.

Any suggestions on this one?

Coen