essay Proof REVENUE STAMPS: 1975-76 R10 and R20 composite essays comprising printed proofs with value affixed, each on card with suggested colour swatches and marked "Approved"; 10R imperforate proofs (2) in brown and black, both on cards with suggested colour swatches and "Approved subject to the red litho printing", and 10R imperforate proof in brown and red, on similar card and marked "Approved"