Can you see invisible ink with glasses?
Invisible ink can be revealed with certain types of heat or light. It is often made from organic liquids such as water, ethanol, or propylene glycol. These liquids are mixed with acid-forming chemicals such as thymolphthalein or methyl ethyl ketone. When the ink is heated (by ironing or holding it above a 100-watt light bulb), the thymolphthalein molecule condenses and the writing appears in white letters. This type of ink is used by printers for recording the serial number and printing date on their paper prints.
The most common way of revealing invisible ink is by using a ultraviolet light. This type is available at most hardware stores. It can be used to reveal invisible ink. However, the ink can also be viewed under a black light or even a regular light bulb.
Some people wear invisible-ink clear glasses to see marked poker cards. These sunglasses have red filters built into the lenses that can detect luminous invisible ink marks on the back of marked cards. This helps to improve the chances of winning a game of poker by making it easier for players to identify the marks. These glasses look normal and are safe to wear. They can be used in any environment, and are ideal for poker games.