Have you ever wanted to send a secret message to a friend that no one else can read? Invisible inks can help you do that! When you use an invisible ink to write a message, it quickly disappears. The ...

A Hillhouse student’s eyes widened as he applied grape juice and heat to what appeared to be a blank piece of paper — but instead held a secret message in invisible ink, written as part of a course ...

When we were kids, “invisible ink” meant lemon juice on notebook paper, write the message, and to see it someone would have to hold it up to the light for the words to appear. Otherwise, it just ...