I believe most stamp collectors are familiar with Inverted Jenny, one of the worlds most prestigious stamp printing errors. But how many has seen the non-inverted stamp (and other stamps of the same set)?
The complete set contains 3 stamps: 6 cents orange, 16 cents green and 24 cents red/blue. They were issued for New York-Philadelphia-Washington airmail postal service (the first of it’s kind in US).
The first stamp issued was 24 cents red/blue on May 10th 1918. US Post Office set a controversial rate of 24 cents for the service, much higher than the 3 cents for first-class mail of the time. The stamps additional price paid for “innovative new service” as well as included special delivery.
For some reason or another, at least one pane of 100 24 cents stamps with inverted center of the design was sold out to customers, creating one of the rarest and most sought stamp printing errors.
On July 11th 1918, a new 16 cent green value was issued. My copy of this stamp is imperforate at the bottom (common for US stamps that are from the sheets edge).
The orange 6 cents stamp (issued in December 10th 1918) is something I unfortunately don’t have (at least yet). So no picture of that – sorry.
You might also be interested of related posts about Stamps and postal history of USA.