I'm having a issue were every uv png I paint and export gust show up as solid black none of the color I added exports. It shows fine in render and everything in blender but in unity or in anything else. its gust solid black.
ok so I think I know exactly what's your problem if you are using cycles to paint your UV maps all you have to do is - create an image texture in the UV image editor give it a name. - go to the node editor and create an image texture node. - select your texture with the left mouse button make sure that it's highlighted in orange color.
- now when you paint it will show up on the UV map and when you exported it hopefully it won't be black
ps: if this didn't solve it pls post a snap of your setup