I do not want my decals to be translucent. I want them to look haw the looked in 4.12 before upgrading engine versions. Is there anything I can do to get non translucent decals (even if there is a performance loss)?
Have you enabled DBuffer decals in your project settings? If you’re using static lighting you may need to do this to improve the appearance of your decals. This article has a description of how to do this: UE4: Solution to Decals Not Rendering/Showing in Indirect Static Lighting Tutorial
Here’s a thread that addresses a similar sounding issue: Decals very transparent under static lighting - Rendering - Epic Developer Community Forums
Otherwise, I’m not sure what might have changed across versions to make your decals look washed out. Some before/after screenshots might help diagnose the issue.