Bridget Riley (British, born 1931) One Small Step (Schubert 70) Screenprint in colours, 2009, on wove, signed, titled, dated and numbered 118/300 in pencil, printed by Artizan Editions, Hove, published by Karsten Schubert, London, with full margins, 441 x 291mm (17 3/8 x 11 1/2in)(SH)