A black torch to darken everything Can we ever have a black colored (the color of the light and not the body's color) torch that darken (or dis-illuminates) everything? While compared to a normal torch it would function in an opposite manner. If not now, will it be possible to create this in the near future?
 A: Black isn't a color. It's just absence of light. So, a torch can't project light having such color.
However, for the second part (dis-illuminate everything), I have an answer: Light is wave and waves can cancel each other. Projecting specially programmed adjustable light wave which create fully destructive interference with other available light waves can achieve your goals. But, the problem is: Full 100% destructive interference isn't possible at this time. You asked for future, so just wait. It may be possible in future.
A: Wow that's an interesting question.  I believe the answer is no, and the reason is that you can have light, or no light, but you cannot have "not light."  If that makes sense.  Darkness is the absence of light, so you cannot really have a material darkness.  
A similar idea is that cold is just a lack of heat.  If you make something cold, it is not because you added cold to it, it is because you took heat away from it.  Similarly, you can only add or remove light, you cannot add anti-light. 
I'm not sure how to come up with something more sci-fi, you might think about this in terms of anti-photons (if they exist re:this discussion).  
