Is it possible to have negative lights in UE4 for baked lighting ? (negative as darkening an area, instead of brightening it)
Quake 3’s lightmapper had such feature where lights with negative power value would darken the area. Useful for all kind of entrances (to make them artificially darker so player couldn’t see clearly what’s waiting for him/her there)
Pretty sure you can’t break the PBR system of lighting that way, but you could make some creative workarounds. Like a blob or plane with an unlit, translucent, depth-faded black material to darken things. Or rely on auto-exposure (or manual exposure bias) to accomplish your example above.
There’s a volume class (I think its the post processing volumes) that you could give a try. Drag it around your room and turn the values you need down, to darken the room.