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Right, I picked the "blurred blue" and "blurred green" pictures, converted them to grayscale using luminance and "blurred blue" still looks sharp and "blurred g
by GuB-42 5y ago
Right, I picked the "blurred blue" and "blurred green" pictures, converted them to grayscale using luminance and "blurred blue" still looks sharp and "blurred green" still looks blurry.
If it really was the effect of blue light, the effect should have disappeared by converting to grayscale.
It is well known that luminance matters much more than color when it comes to perceived sharpness. Digital and analog video exploit that by encoding color at a lower resolution (chroma subsampling). And blue only accounts for less that 10% of luminance while green is around 70%. You may find different values because color spaces are a mess but that's the general idea.
- Retric 5y agoThat’s not an apples to apples test because of how greyscale is computed. Try swapping the blue and green channels rather than converting to greyscale.
- skupig 5y agoI think for a proper comparison, you would need to swap them by perceived brightness (luminance), not just the RGB value. You can't do that here because the green channel in this image is out of the possible range of luminance you can achieve with blue (in any standard color space, probably). Which really illustrates why TFA doesn't make any sense- our eyes are less sensitive to blue, so the contrast provided by max RGB value blue is going to be completely drowned out by red and green if the source of your contrast is white on black. Here's what it looks like with all channels shifted to have the same luminance: https://i.imgur.com/AnKNdfX.jpg https://i.imgur.com/AnKNdfX.jpg - note it is perhaps a little softer as the peak brightness is closer to black. Now here's what each channel looks like blurred by 2.5px: https://i.imgur.com/XzVWeZg.jpg https://i.imgur.com/XzVWeZg.jpg https://i.imgur.com/LB5JArJ.jpg https://i.imgur.com/LB5JArJ.jpg https://i.imgur.com/jf4ntth.jpg https://i.imgur.com/jf4ntth.jpg They're all clearly fuzzy in comparison to the un-blurred image. The answer to "why we're blind to the color blue" is not chromatic aberration (although it could be a contributing factor, maybe even why we have less blue receptors), it's that we're less sensitive to blue and therefore contrast is usually defined by red and green.
- Retric 5y agoPerceived brightness is very tricky as our vision naturally adjusts to normalize perceived colors. https://en.wikipedia.org/wiki/The_dress https://en.wikipedia.org/wiki/The_dress Personally I don’t see each image as equally blurred, but YMMV.
- analog31 5y agoThere's a difficulty with testing perceived color by using a computer display, which is that the "blue" is the spectrum of the blue pixels, whereas the "blue" receptors in your eye may have a different spectral response. Where I've noticed weird things with blue are with blue sources that have fairly short wavelengths, such as some of the blue LEDs used in Xmas tree lights, and the old blue lights that were on police call boxes. Both of those are very hard for me to focus on.
- moralestapia 5y ago>such as some of the blue LEDs used in Xmas tree lights, and the old blue lights that were on police call boxes. Both of those are very hard for me to focus on This happens to me as well and I though I was becoming blind (to blue light) because of my heavy use of monitors/"white" light, etc...