Home >> Science & Nature >> Science

How to Make Invisible Ink That Works

There are many different substances that can be used as invisible ink. Many of these are inexpensive and commonplace. These substances become invisible after drying on paper and then become visible again when exposed to a stimulus -- these stimuli are normally chemical reactions either with the ink or the paper the message is written on. Anything from lemon juice, to milk, to cornstarch can be used as invisible ink if the correct revealing stimulus is known.

Things You'll Need

Baking soda
Water
Cotton swabs
Concentrated grape juice
Milk
Lemon juice
100-watt incandescent light bulb
Cornstarch
10-percent iodine solution
Hotplate or oven burner
Toothpick

Instructions

Invisible Ink Recipes
- 1
  Make a solution of equal parts baking soda (sodium bicarbonate) and water and stir it thoroughly. Dip a cotton swab into the solution and write a message on a sheet of paper. Allow the solution to air dry completely. Expose the message by brushing concentrated grape juice lightly over the paper.
- 2
  Dip a cotton swab into milk or lemon juice and write a message on a sheet of paper. Allow the substance to air dry completely. Hold the paper over a 100-watt incandescent light bulb to slowly heat it and reveal the message,
- 3
  Make a solution of 1 part cornstarch and 2 parts water and stir it thoroughly. Heat the solution on a hotplate or an oven burner set to low. Dip a toothpick or cotton swab into the solution and write a message on a sheet of paper. Allow the solution to air dry completely. Expose the message by applying a light coating of a 10-percent solution of iodine (1 part iodine to 10 parts water) to the paper.

Science