Stanley William Hayter did this work using engraving and scorper on 2 plates, which he printed side by side, the left being intentionally higher. He used alkalai blue, printed intaglio and a phthalo green with a hard roller on the surface.
The printing sequence was done in three states, the first with engraving, done in a single proof; the second adding further engraving and scorper, also in a single proof; the third added further engraving and was editioned as thus: color trial proofs, 5 artist's proofs and an edition of 50, finished in three printing campaigns, 8 in 1967 and then Hector Saunier printed numbers 9 through 18 in 1968, finishing the edition (numbers 19 through 50) in 1969. This impression is from that final printing.