The problem with cheap 4k projectors is that they are pixel-shifted 1080p projectors. Combine that with DLPs colorwheel tech, and you are relying persistence-of-vision to combine at least 12 frames into one image. It's kinda neat that it works at all, but if you are sensitive for temporal hijinks then its not great solution to all-day use.

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buffington 7 months ago | parent [-]

Do you know of any good write-ups on how this works? I've often thought I was crazy for noticing weird "glitches" when around some of the newest projectors.

I'll see "sparkles" or flashes of a solid color out of the corner of my eye, but never if I try to look directly at the screen to catch it. I chocked it up to some sort of PWM based lighting or something that's more detectable in my periphery because of how cones and rods work. Sounds like I might be close, but not quite?

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brokenmachine 7 months ago | parent [-]

Consider getting your eyes checked - visual field test, etc. I believe sparkles in the periphery can be a sign of glaucoma and probably other nasty stuff. I know you're talking about when looking at a projector but maybe your peripheral vision could be affected and this is how it presents.

	▲	buffington 7 months ago \| parent [-]
		Never bad advice to get your eyes checked, but I may not have described it well enough. I used to see a similar thing with a flatbed scanner that used RGB LEDs instead of a CFL tube. You could often see the flicker of the PWM signal they were likely using to control the brightness of the LEDs as solid flashes of red, blue, or green. GP post said: "if you are sensitive for temporal hijinks" - I think I'm just really sensitive to temporal hijinks, especially in my periphery. I suspect most people are, as our eyes have higher concentration of rods to detect movement in our peripheral vision. I've noticed that the quality of light I get out of a constant current light meant for videography is fantastic and has none of these "temporal hijinks", and I think it's because it simply doesn't flicker. Still - none of this is said to undermine your good advice.