Materials from the Postmaster General's Collection

Sikorsky Helicopter

refer to caption — 36¢ 1988 Sikorsky airmail stamp

This 1988 airmail stamp honoring aviation pioneer Igor Sikorsky is one of a handful of U.S. stamps produced with gravure and engraving—a technically difficult combination. Most of the stamp was printed in gravure, but the crisp VS-300 helicopter was produced with engraving.

Like many modern U.S. stamps, this one includes a “taggant” visible only in ultraviolet light. Taggants allow sorting equipment to locate stamps on envelopes. They can be embedded in the paper or added as a coating; here, a tagging ink was mixed into the special light blue ink.

Artwork, Model, and Die Proof for 36¢ 1988 Sikorsky Airmail Stamp

*Original artwork, 36¢ 1988 Sikorsky airmail stamp*

*Approved working model, 36¢ 1988 Sikorsky airmail stamp, signed by Fletcher Acord, Associate Postmaster General, December 1987 (shows value as 44 cents)*

*Die proof, 36¢ 1988 Sikorsky airmail stamp*

Proof Sheets for 36¢ 1988 Sikorsky Airmail Stamp

These proof sheets include “progressive proofs” for the gravure portion of the stamp—which progress from one color of ink to all five inks, adding one ink at each stage—and separate one-color proofs for each color. In addition, they include a proof sheet that’s only for the engraving portion of the stamp, and a final proof sheet that combines both gravure and engraving.

36¢ 1988 Sikorsky Airmail Stamp Progressive Gravure Proof Sheets