light trick

[CryptbornAkryea]

It seems I've read mention of some 'low light' trick. I gather it has something to do with using a source of lesser illumination to trump a source of greater illumination.

What are the facts concerning this?

[Gildedragon]

The one I know is to use darkness to make an area less dark, as darkness produces shadowy illumination and not actual darkness or lowering of ambient light. Thus in darker than shadowy areas Darkness actually produces light