Stamp Market Tips by Henry Gitner and Rick Miller
Stamps generally begin life as essays (proposed designs). After the design is approved, trial printings are taken from the engraved plates before the stamp is issued.
These are called plate proofs.
Proofs are normally printed on India paper or card stock. Card proofs are printed on high-quality, clear white card stock, which can vary in thickness.
Card proofs are ever popular with specialist collectors of U.S. stamps. Plate on card proofs of the 1873 Departmental Official stamps (Scott O1-O93P4) serve as good examples of this popularity.
Connect with Linn’s Stamp News:
Complete sets with decent margins, fresh colors and neatly hinged or undamaged backs are a good buy at 80 to 100 percent of the 2018 Scott Specialized Catalogue of United States Stamps and Covers values. This also applies to individual Departmental sets.
Vibrant color is especially important with the Executive, Navy, Justice and War Departments proofs as these are the ones most likely to fade.