Ruku-Grey is a synthetic paper with a matt grey face that emulates the qualities of raku pottery under dry glaze. It supports the aesthetic of inks much more gently than black but holds its own with contrast and interference throw. It's tough, pretty firm at 200 gsm - although not a board by any means. I love it. I've been spraying boards with multi-coats of charcoal for a long time trying to achieve this look and now all the work is done for me. Inking straight onto this substrate is a treat.