The purchase of this stamp/s will earn you 3 points valued at $0.05.
The Total Eclipse of the Sun stamp is the first U.S. stamp to use thermochromic ink, which reacts to the heat of your touch. Placing your finger over the black disc on the stamp causes the ink to change from black to clear to reveal an underlying image of the moon. The image reverts back to the black disc once it cools.
Total Eclipse of the Sun Stamps
The Total Eclipse of the Sun Forever stamp uses thermochromic ink for this first of its kind stamp issue. This process used to create the stamp involves layering ink. Since this is not our traditional method of printing, it will not have the traditional smooth, tight appearance.
The heat of your touch is usually enough to activate the thermochromic ink but there are other factors that could influence this effect, such as lower body temperature, cooler extremities, or cooler room temperatures. Since body temperatures differ, you may have to use an additional source of heat such as a lamp to reveal the image. When the temperature of the paper cools the image will revert to the black disc. Again, room temperatures can affect transition. In an overly warm room it may be necessary to cool the stamps by placing them in an area which is substantially cooler than the room temperature. Thermochromic inks are vulnerable to UV light and should be kept out of direct sunlight for extended periods of time. Excessive exposure to UV light could affect the changeability of the ink, resulting in a permanent clearing of the ink to reveal the moon.