StampShow 2009 will include a star appearance by an "Inverted Jenny," the most famous US misprint, among the rare stamps on display.
Printed in 1918 when airmail was new, one sheet of the 24-cent stamp was printed with the Curtiss JN-4 airplane upside down. A block of four Inverted Jennies sold for $2.9 million in 2005.
Acting society president Ken Martin says there will be a big competitive display, some 900 frames presented by 150 individuals. Each frame - or page - holds 16 stamps.
The four main judging categories are: Title and Treatment; Knowledge, Study and Research; Rarity and Condition; and Presentation.
Other attractions will include a trade show with 150 firms selling stamps through auctions. As many as 15 meetings and seminars will be going on at the same time.
Cheryl Ganz, curator of the Smithsonian National Post Museum in Washington, says the appeal and value of stamp collecting has many aspects.
"Stamp collecting is great for kids between 7 and 12 because they learn about history, geography and culture, and also organisational skills."
"A lot of founders of the Internet were stamp collectors. It helped their thinking to develop. Kids who collect stamps tend to have higher SAT scores and are high achievers in life."
Ganz is bringing wit her the largest block known of the first stamps issued by Peru in 1847.
Elsewhere, a 10-frame exhibition of stamps centred on baseball legend Roberto Clemente will be brought along by a Pittsburgh collector. It will include a commemorative stamp issued in 1984, billboards and first-day covers.
There are an estimated 48 million stamp collectors, worldwide. StampShow 2009 promises to show that the passion of collectors is as strong as ever.
StampShow 2009 will be held August 6-9 at the David L. Lawrence Convention Center, 1000 Fort Duquesne Blvd., Pittsburgh, Pennsylvania.
