Message #283

From: Don Hatch <>
Subject: Re: [MC4D] Stereo!
Date: Sun, 18 Jun 2006 00:43:30 -0700

On Thu, Jun 15, 2006 at 11:33:36PM -0500, Roice Nelson wrote:
> I made it so that stereo would work correctly with the red filter over
> your left eye when displaying the puzzle on a white background. If
> you leave the background the default black, you’ll need to reverse how
> you wear your glasses so the blue filter is over the left eye. I had
> never known this until playing with it, but different background
> colors reverse what gets filtered out. For white backgrounds, the red
> filter shows the cyan color, but for black backgrounds, the red filter
> shows the red color. I don’t understand this, but it is true! I bet
> there is some color theory explanation or something.

I never realized that before, but it makes sense…
The red filter only lets through red,
and the cyan filter only lets through green and blue.
So if you look through the red filter:
white -> red
red -> red (so you can see it on a black background but not a white one)
cyan -> black (so you can see it on a white background but not a black one)
black -> black
And if you look through the cyan filter:
white -> cyan
cyan -> cyan
red -> black
black -> black

Don Hatch