This card looks rather corrugated to me. Or maybe like aged, rusting metal. I took my postcard and glued down strips of crumpled wax paper. I painted over them lightly with black acrylic to pick up the ridges. Once dry I painted between the strips with glass bead medium. Then I went over the black with a turquiosy green using a palette knife. I added some blue and black to that color and painted and palette knifed it over the entire surface to tone it down. It has a rough, aged look to it and yet the glass beads give a bit of shine and added texture.