I may have asked this before:

Matthew 6:23 But if thine eye be evil, thy whole body shall be full of darkness. If therefore the light that is in thee be darkness, how great is that darkness!

Is there such a thing as "dark light"?

It doesn't say, here, that there is no light, but that the light is darkness.

It sounds like the very light itself is darkness.

Would a flashlight of dark light darken whatever it is pointed at, making shadows where there were none?

Shadow-beams?

Is that the kind of light there might be in hell?

By contrast, will the new Jerusalem have no shadows, or any kind of darkness at all?

Revelation 21:23 And the city had no need of the sun, neither of the moon, to shine in it: for the glory of God did lighten it, and the Lamb is the light thereof.

  25 And the gates of it shall not be shut at all by day: for there shall be no night there.