How to increase effect of light without increasing intensity

Hi,
I want to increase the effect of light without increasing intensity
image
I have to make the middle part visible from only light from the wall, i know i can use skylight but i don’t want light in other parts of the map.

You need to create a material with an emissive property and force it to only show up in the Lumen Scene. Apply this material to a mesh and put it into the world.