Okay, so we sent this stamp design out in a few different month's boxes in 2017. But we were totally unaware of it's magical powers!! The Total Eclipse of the Sun Forever Stamp, which commemorates the August 21, 2017 eclipse, is a first-of-its-kind stamp that changes when you touch it. It transforms into an image of the Moon from the heat of a finger!
Tens of millions of people in the United States viewed this rare event, which had not been seen on the U.S. mainland since 1979. The eclipse traveled a narrow path across the entire country for the first time since 1918. The path ran west to east from Oregon to South Carolina and included portions of 14 states.
The stamp image is a photograph taken by astrophysicist Fred Espenak, aka Mr. Eclipse, of Portal, AZ, that shows a total solar eclipse seen from Jalu, Libya, on March 29, 2006.
In the first U.S. stamp application of thermochromic ink, the Total Eclipse of the Sun Forever Stamps reveal a second image. Using the body heat of your thumb or fingers and rubbing the eclipse image will reveal an underlying image of the Moon (Espenak also took the photograph of the Full Moon). The image reverts back to the eclipse once it cools.
Thermochromic inks are vulnerable to UV light and should be kept out of direct sunlight as much as possible to preserve this special effect.
Art director Antonio Alcalá of Alexandria, VA, designed the stamp.