Identifying Tagged Stamps - Do it, But Do it Safely

When printing their stamps, many countries use special paper, a special coating on top of the design or a special underprinting that glows when exposed to ultraviolet light. These stamps are called tagged stamps. Sometimes you can see evidence of tagging under regular light, but a UV lamp is almost always required. Tagged stamps facilitate faster mail processing by allowing automated sorting equipment to be used by those countries' postal authorities.

Collecting tagged stamps requires a stamp collector to use a UV light source, but because these lamps are dangerous to your eyes, never look directly into the lamp. Relatively short exposures to UV light can burn the corneas of your eyes. Wear glasses if you can when using a UV lamp to check the tagging on your stamps: the plastic or glass of the lenses in your glasses will absorb some of the UV light and help to protect your eyes. It's also helpful to identify tagging as quickly as possible, so sort your stamps as much as possible before turning on the ultraviolet lamp.

Tagged stamps often have tagging varieties and tagging errors. Some US stamps have several different types of tagging, even though the stamp design is identical. Tagging can be challenging, but it also can provide hours of pleasure. But please do it carefully.