The 50¢ Proprietary is listed as Essay 65 in George Turner's Essays and Proofs of United States Internal Revenue Stamps (1974) — indicating die proofs printed in both black and blue, blue being the color an issued stamp would have been printed in.
It references the Clarence H. Eagle Collection as the source of this information.
Eagle had acquired both proofs from Hiram Deats, along with a great deal of other Butler & Carpenter material originating from the fabled purchase made by E.B. Sterling from the government in the late 1880s. Deats was one of the authors of the 1899
Boston Revenue Book, which recorded the circumstances leading to the creation
of the 50¢ Proprietary essay, though its actual purpose puzzled the authors.
Eagle's collection went by bequest to the Library of Congress upon his death in 1922.
In 1958, the collection was transferred to the national philatelic collections of the Smithsonian Institution. When the National Postal Museum was created in 1993, the collection was transferred there along with the Smithsonian’s other philatelic holdings.
The Eagle Collection at the National Postal Museum in fact does not include either of the 50¢ Proprietary essay proofs — Morton Dean Joyce had acquired them.
Offered here is the blue proof — the only existing impression of this never-issued stamp design in the color it would have been issued in.
Why Was It Created?
The Civil War era First Issue revenue stamp series never included a "Proprietary" titled stamp with a denomination greater than 10¢.
However, in September 1864, a 50¢ Proprietary stamp was briefly considered as part of a plan to give photography studios the option of paying the tax by submitting high-denomination stamps with their monthly returns, instead of affixing low-denomination stamps to every photograph.
The plan was almost immediately abandoned, but not before the government's printer, Butler & Carpenter of Philadelphia, had prepared the design and produced die proofs.
Proprietary stamps denominated higher than 10¢ (50¢, $1 & $5) were first issued in 1873 in the new bi-color designs of the Second Issue.
How Did I Get It?
The blue die proof does not appear in the catalog of the first Joyce sale (June 4-6, 1991/Daniel F. Kelleher Co.) because I purchased it privately before the auction was organized. Only the black proof was offered at that sale.
The 50¢ Proprietary Blue will be delivered mounted to its exhibit page from my Civil War Sun Picture Tax philatelic exhibit. It had been featured as a key item in this gold medal exhibit for over 20 years.
A worthy addition to even the most advanced private or institutional collection — a once-in-a-lifetime opportunity for connoisseurs of fine American philately and the history of Civil War era taxation and photography.