This started as a coloured pencil drawing of a piano keyboard on black card, the problem I came up against was getting the keys pure white. I tried dry brush with oil pastel with prismacolor on top, still too dull. So I put it away. Eventually I brushed on Acrylic Ink (several coats) and this is the end result, Definitely mixed media.
Black Canson 220gsm card, Prismacolor pencils, oil pastels, white acrylic ink.