I cant say for sure. Somehow, I tested other objects using light colors. They dont seem to have this issue at all. Any dark textures seems to be…100 times darker. I tried placing light points, spotlight, ambient lights to intensify the lightness on the object. It doesnt seem to have any satisfying result. Looks like i might need to study more into nodes I feel like i messed up in that section resulting into this poor lighting quality.
Okay so I downloaded a random mesh from turbo squid for texturing tests so i ended up texturing it using substance painter. I saved the textures file in targa format including emissive, metallic, height etc. However, it did not turned up to be exactly how it should in unreal engine 4. Am i missing something here?