luminous ink for contact lens

How to make luminous ink for contact lens? print the luminous ink on the back of card. When you applying contact lenses, you can see the numbers and symbols ,This invisible ink is invisible to the naked eye and can only be seen by contact lenses-cycheatpoker

Transcript

2. • Invisible light refers to light that is invisible to the human eye, including ultraviolet rays, infrared rays, and far infrared rays that we are familiar with. The wavelength of electromagnetic waves that the average human eye can perceive is between 400 and 700 nanometers. We used this feature to make high-tech invisible ink
3. • I remember a kind of contact lens used on magic show when I was young. They used a special ink to make a mark on mahjong or playing cards. The mark became visible after wearing the contact lens.
4. • luminous ink: ethanol solution of phenolphthalein • Formulation agent: sodium hydroxide solution • Phenolphthalein is a commonly used indicator in chemistry and turns red when it encounters alkaline sodium hydroxide.