I made this postcard, as the other, with a stencil and some modeling paste and a pre-made postcard ground with black on one side and paler paper glued to the other. After I did it, I let it dry and then started layering different colors over it, which mostly stuck only to the raised surface. None of this is mica pigments, as it looks. It’s all metallic paint. The modeling paste makes the card thicker, but I’m pretty sure it will still mail just fine.