Stamp box directory

EKKP stamp box: dates and marks

If the stamp box on the back of your real photo postcard carries this mark, the paper’s production window narrows the card’s date. A stamp box dates the paper, not the photograph — read the range below as “no earlier than,” and let a postmark set the latest possible date.

Standard mark

1904-1950

The front of a real photo postcard of the San Francisco-Oakland Bay Bridge under construction, from the Postcard Origins collection — A real photo card of the San Francisco–Oakland Bay Bridge under construction, by the Piggott Co. of San Francisco.Scanned from the Postcard Origins collection

The EKKP stamp box on the back of the same card — The EKKP box spans 1904–1950 — a wide window. The *subject* pins it: the bridge was under construction only **1933–1936**. Here the photograph out-dates the paper.From the collection

A custom triangular stamp box reading Piggott Co. San Francisco — From the collection

Not every stamp box is a paper brand. On another Bay Bridge card in the collection, the stamp box is a custom triangle reading PIGGOTT CO. SAN FRANCISCO — the photographer’s own studio mark sitting where the stamp goes, with no paper brand at all. When the box is a studio’s own, date the card the other way: by subject, postmark and stamp.

Ranges cross-checked across: the2Buds.com chart, as republished by Sports Collectors Daily, ‘Dating Vintage Real Photo Postcards’; SABR Baseball Cards Research Committee, ‘Dating and Authenticating Real Photo Postcards’ (2017); Postcards Everywhere collector chart (2010); Playle’s Directory of Stamp Boxes (playle.com, frozen reference; marketplace closed 2020). Approximate by nature — see methodology.

All stamp boxes Dating wizard