1913 Romanov Tercentenary 50k frame only die proofs in reddish brown and orange, with the names of designer and engraver beneath the picture, fine. Possibly from Tsar collection R. Lowe 1935 as described “50 kopecks: … Fifty-seven die proofs of the frame in different shades …” published in the Yamschik-Post Rider 1983, No 12, page 15.