Lot 30104 – 1913 Romanov Tercentenary 70k bi-colour proofs on chalk-surfaced paper, four examples

1913 Romanov Tercentenary 70k bi-colour proofs on chalk-surfaced paper, four examples in different colour combinations of frame and vignette, with the names of designer and engraver beneath the picture, odd small thin at top. Possibly from Tsar collection R. Lowe 1935 as described “70 kopecks: … Eighty-five bi-color die proofs of the complete stamp in various colors…” published in the Yamschik-Post Rider 1983, No 12, page 15.