Decode Red - Part 222:26 Min May 2026

To create a "DECODE RED" activity—a popular project where a hidden message is revealed using a red filter—follow the steps below. This activity is designed to take roughly to complete. Materials Needed Paper: White construction paper or cardstock.

Cut a piece of cardstock into the shape of a magnifying glass or a simple rectangle with a hollow center. DECODE RED - Part 222:26 Min

Use a to scribble, doodle, or write "decoy" words directly over your blue/green message. To create a "DECODE RED" activity—a popular project

The goal is to cover the blue message enough that it is no longer readable to the naked eye. The red ink should look like a chaotic jumble of lines or shapes. Cut a piece of cardstock into the shape

Cut a piece of slightly larger than the hole and tape or glue it over the opening. This will act as your "secret lens" that reveals the hidden text. Write the Secret Message (5 Mins)

If you don't have red cellophane, you can create a "heat-decode" paper using . Write your message with juice and a brush; once it dries (about 15–20 minutes), hold it near a heat source like a lightbulb or iron to turn the writing brown and "decode" it. Write a Secret Message with Matt!

Place your red decoder lens over the paper. The red filter will make the red marker "disappear" into the background, while the blue or green text will appear dark (nearly black), making the secret message clearly visible. Alternative Method: Invisible Ink