Polarized Hidden Messages
Another Covert Public Message


Inspired by movies like "They Live", "The Spiderwick Chronicles" and countless spy films, I wanted to create a means of displaying information in public, that only a select few could see.

This project was also written up for Make Projects with new pictures and details: Polarized Hidden Messages

To the unaided eye, the mosaic of tinted film squares seems uniform and holds no particular meaning.

But when viewed though a polarized filer (or a pair of polarized sunglasses), the concealed message becomes clear.

I designed this project to display letters using squares of polarized film, a 5 by 7 matrix (a format used by most illuminated signs) composes each letter. The squares that make up the letter are rotated by 90 degrees in respect to the background squares. In normal light, the human eye has trouble differentiating the letter from the background. But when viewed through a polarized filter (such as a pair of polarized sunglasses), the message becomes visible.

The polarized film was purchased from http://www.polarization.com/ a wonderful and helpful resource for your polarized needs.

Practical applications include

  • Informational overlays that could be visible on demand, so as not to be distracting or add to visual clutter.
  • Secret messages only those wearing sunglasses
  • Subliminal mind control
  • Directions to a very secret party
  • REALLY targeted advertising
  • House numbers for those who don't like unexpected visitors

 I would like to expand this concept to an automated mechanical sign, but have been unable to locate an affordable flip-dot/flip-disk display (like they used on buses and in airports before the current LED based signs). If anyone has information on obtaining one, please contact me.