UE4 automatically adjust the brightness of what you are looking on screen. This featured is called eye adaptation. The reason why it’s brighter in one scene it’s because the background is darker or something, and UE4 tried to compensate.
Eye adaptation:
here’s a few ways to disable it:
Hi, I’m currently working with a programmer to make an educational game for kids. As shown in file number 2, the emissive map worked great when i created a new scene but for some reason, when i applied an exactly same material on a plane object in a scene the programmer gave me, the glowing effect scaled down to almost zero as you can see on file number 1. I wish to know what’s causing this. I assume that this is quite basic problem but i just don’t know cuz i’m too nub at this engine… I hope you can help me out on this! appreciate your help in advance.
Thank you for your quick reply! I followed your instruction but It didn’t solve the problem… If I’m right the glowing happens when things move in and out of dark or bright area but as to my case, the glow is there constantly.
I found some difference between the 2 materials though. First image is the one with glowing effect properly working and the second one is the one that’s not working properly. Does this have something to do with mobile stuff…??
hi, i know i’m kinda late to reply, but maybe someone else would benefits from this 
you have a post process volume in your scene, right? if so … try adjusting the “Bloom” section under Settings … increase the intensity, if you don’t have one simply drag one from your mods panel on the right into the scene.
note if you have a big scene select your post process volume and scroll down then check the box that says “Unbound”.
another thing you can do is in the material editor try multiplying whatever plugged into emissive color by a “Constant” or “Scalar Parameter” using the “Multiply” node,in first pic the light color is being multiplied by 1 and the second pic is multiplied by 20.
