Okay, I found out what is happening, which I didn't quite realize.  If you export using "Diffuse" for a texture,  the color will be darkened where ever there is Metalness painted.  You can see the image below for descriptions (Hovering over stuff in 3d Coat often gives you a description).   What seems weird to me, is that changing the Texture Workflow doesn't seem to do anything for me.  "Color (albedo)" seems to get the color information despite being set to "gloss/specular" workflow. Anyway, if you are using Metalness and your paint layer's Metal Opacity is above 0%, then Diffuse will be darkened.  So, you need to export "Color (albedo)" and not Diffuse.  If you are not using Metalness, or your Metal Opacity in your paint layers is set to 0%, then you can export with Diffuse and still receive color information. If anyone wants to clarify or expand on this, please feel free to interject.  
    • Like