Earlier quoted context omitted.
I'm pretty sure it's not interlacing faster than the eye can see, which is the whole problem. For this to work perfectly, your monitor refresh rate would need to be at least 2x higher than what your eyes can detect. And why would anyone build hardware with such a fast refresh rate? It's a cute idea, but in the end it ruins the image for normal uses just like the watermarks do.
Well, the website's down, so I can only speculate, but, how is the website to know the screen's refresh rate? If the site assumes, say, 60 Hz, but the rate is actually 72 Hz, you'll see an odd "fading" effect between the two interlace frames at a rate of 12 Hz, which is very noticeable. EDIT: Ah, I see he uses window.requestAnimationFrame [1] to sync with the frame rate, so this is not a problem. [1] https://develope…
Here's the relevant code from the demo:
var work = (function() {
var toggle = false;
return function tester() {
frame1.style.opacity = toggle?.5:1;
frame2.style.opacity = toggle?1:.5;
toggle=!toggle;
requestAnimationFrame(tester);
};
})();
requestAnimationFrame(work);