Large Die Proofs (P1)
These are impressions taken directly from the original master die.
Material: Printed on thin, smooth, often cream-colored, strong paper, usually India paper.
Appearance: This paper was favored for its ability to absorb fine detail from engravings, resulting in a crisp, sharp image.
Usage: These were often used to check the quality of the engraving or for official archives.
Mounting: India paper proofs were usually mounted (die sunk) on a stiff backing (like white or blue card) to give them strength, as the paper itself is very thin. The backing usually had wide margins in order to showcase the stamp
Small Die Proofs (P2)
These are impressions taken directly from the original master die.
The material, appearance and usage was the same as large die proofs. The difference being that they are trimmed to a smaller size, typically just slightly larger than the stamp itself.
1903 Roosevelt Edition Small Die Proofs
Produced for the "Roosevelt Albums" presented to the President and other high-ranking officials, these were printed by the Bureau of Engraving and Printing (BEP). Description: Printed in red-brown on gray-white cardstock that was then trimmed to a small size (approx. 25mm x 30mm). Unlike the original stamps, these were pulled from the original die but often show a much cleaner, more detailed impression than the issued stamps.
1915 Panama Pacific Proofs
From February 20 to December 4, 1915, the Panama-Pacific Exposition was held in San Francisco, to commemorate Balboa's discovery of the Pacific Ocean and to celebrate the opening of one of mankind's greatest engineering achievements, the Panama Canal. The Post Office Department decided to prepare a limited number of proof sets showing every United States stamp printed up to the time of the exposition. A total of 413 different designs were made. Only two sets were officially prepared, but it is widely recognized that between three and five of each were made. These included Officials, Newspapers and Periodicals, Philippines and other special use stamps.
Plate Proofs (P3)
These proofs were typically produced during the early stages of production to test the printing plates before the final run. Otherwise they have the same characteristics as small die proofs described above.
Proofs on Card (P4)
Printed when the plate was fresh. They were printed in much higher numbers that the P1, P2 and P3 proofs, therefore they are more accessible to collectors.
Material: Printed directly onto stiff, thicker, high quality, white card or cardboard, usually without India paper.
Appearance: Known for vivid colors and "razor-sharp" impressions.
Usage: Plate proofs on card are often seen from later reprints or to demonstrate the final product, known for having a very high-quality look.
Mounting: They do not need to be mounted on a separate backing because they are already on stiff, thick card.
Trial Color Die Proofs (TC)
These were produced during the initial design and testing phase to determine the final color for the issue.
Description: These exist in a variety of non-issued colors, usually including black. They are typically found on large pieces of bond paper or India paper (Large Die Proofs) and lack the plate-position characteristics found on plate proofs.
Hybrid/Reprint Die Proofs (1881 & 1947)
These were created for exhibitions or anniversaries rather than postal production.
Description:
1881 Atlanta Exhibition: Five color varieties printed on India paper for exhibition sheets.
1947 CIPEX: Created from newly engraved dies for the Centenary International Philatelic Exhibition; these are slightly larger than the originals and sometimes feature cross-hatching or other design modifications.
