Not sure if this has already been covered somewhere but in my level, I have 2 lights in different areas where I only need very little light.
I set the range value to 50 and built the level.
While ingame, there are no visible light sources in either of those spots.
Using the latest public beta.

Thanks

The latest public beta? There are no public betas at the moment. - You can see lights only when a shaded surface intersects their range.

6.40.5 is not a beta? . and NO, the light is not showing up on the shaded surfaces when the range is at 50. - At least not in my level.
If I set it to 75 or above, it will show up. But thats more than I need for that area.

You could set the range to 75 and draw down the light intensity by decreasing all three color values if you don't want to move the lights closer to the surface they should intersect. A color setting of 50,50,50 dims the light quite a bit.
cheers
tindust

Yes. If the light does not reach the surface, either place it closer to it, or increase the light range. Lights are not pixel-precise. For higher precision, set the High prec flag of the light, and make also sure that the light calculation is set to high quality. - I'm moving this to the level design forum.