hi – one method could be …
1) —- duplicate footage of hall
2 ) —- colour correct this copy to get the look you want
3 ) —– on colour corrected duplicate draw a mask / use a circle mask – around area you want darkened and experiment with feathered edging till it blends in with original
– also shape of mask if you need to —– till you have it.
—- would try a circle first as its an easy one but my guess is rhat if you use the pen tool you might get a more convincing result – depends on whats in the shot.
— suggest also experiment a bit — might be worth adding a second copy and darkening further the very centre / or the corners —
— maybe add some grunge texture ( in perspective and apply to walls ) —- blood on the floor ( ! ? ) — depends……
—————————— chris —