Glasses with invisible ink are a special pen that lets you write messages on surfaces like paper, plastic or other surfaces. The glasses work by revealing a hidden pattern or message using a color changing reaction. Some of these chemical reactions are triggered with light, while other are triggered using specific chemicals or chemical combinations. Some invisible inks use oxidation-reduction reactions, in which one chemical reacts with another to change color. These types are called sympathetic invisible inks.
Under a variety conditions, invisible ink can be viewed. This includes sunlight and blacklight. It can also be made visible by exposing it to UV light or other chemicals. Some invisible inks contain phosphor and can be visible when exposed to UV light. These are commonly used to mark products in production or to mark event tickets for readmission.
Some invisible inks use organic materials, such as lemon-juice, that oxidize at high temperatures and turn brown. Heat can reveal other inks, such as by placing the paper over a heater, iron, or 100-watt bulb. This is a quick and easy way to create invisible ink. It can be used to mark documents or cards for privacy.
You can use glasses that can read invisible ink to read marked cards when playing poker. They are comfortable to use and look just like normal sunglasses, so that other players will not be able detect them. The clear version of these glasses is ideal for playing poker as it allows you to see the marks on the backside of marked decks clearly.