Subpixel Text Encoding - msarnoff.org

Subpixel Text Encoding

Matt Sarnoff, 10.22.08

Each pixel on your monitor is actually<br>composed of three sub-pixels: one red, one green, and one blue. On an LCD monitor, subpixels are<br>usually three thin strips in a row (though on some monitors, they may be three bars arranged<br>vertically).

For some time, manufacturers have developed ways to smooth the appearance of text and shapes by<br>taking advantage of this increased resolution; Wikipedia<br>can explain it much better than I can.

I was thinking about this, and I decided to try something. I made this image:

At 12x zoom, it looks like this, just a few innocent columns of pixels:

However, on a standard LCD monitor, if you look at it really closely,<br>or with a magnifying glass or digital camera, you see this:

Then I made this image:

Here it is at 1200%:

It appears to be a jumble of pixels, but if you look closely at the screen, we see:

By using 2x5 grids for each character, you can create more detailed 5x5-subpixel characters.<br>Since the blue phosphor in the rightmost column is never used, it can serve as a separator<br>and allow characters to be placed right next to each other without a pixel in between. However,<br>the characters are slightly more recognizable to the naked eye at actual size.

The technique probably isn't useful for encryption or steganography, but it does look cool.<br>It could be used to create small text "microdots"<br>to exchange with your friends. Unfortunately, on CRT monitors or some LCDs with different subpixel<br>layouts, the effect cannot be seen correctly.

Here's one more hidden message:

At 12x:

And the message revealed:

Photos were taken with a Canon PowerShot SD800 IS (7.1 megapixels) using Digital Macro mode.

Images were displayed on an Apple 30" Cinema Display.

msarnoff.org