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Splice1138 t1_j7m56uj wrote

Reply to comment by TrumpterOFyvie in TIL the first Blue LED wasn't commercially available until 1989 and bright blue LEDs weren't available until 1993. by j-merc23

You might be a more extreme case, but human eyes can't focus on blue light as well, period. I know this first hand (and second, and third) from calibrating three tube RGB projectors back before LCD/DLP.

I also read about it being used in image compression. If you split an image into R, G, and B channels, you can save the B at half resolution and the difference is nearly imperceptible to human eyes, whereas it is easily seen if you do that with R or G.

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Ok-disaster2022 t1_j7mdrk1 wrote

It's frustrating that the headlights from heall are more blue tinted, so no only ate they brighter, but the person using them can't see as well, so they make them even brighter.

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Couldbehuman t1_j7mv5wo wrote

>I also read about it being used in image compression. If you split an image into R, G, and B channels, you can save the B at half resolution and the difference is nearly imperceptible to human eyes, whereas it is easily seen if you do that with R or G.

Never heard of chroma subsampling happening in RGB, generally that's converted to something like YUV which is a Y channel of luminance (about 58% derived from the green channel) and two UV chrominance channels. Both channels of chrominance are then subsampled horizontally by 50%, reducing 1/3 of your original data without even getting to the compression stage. Pretty much all compressed video you ever watch has the chrominance subsampled 50% vertically as well, meaning you've cut the original data size in half.

Point is, not just blue getting subsampled, and since that's what everyone is constantly watching it's pretty safe to say it turned out alright.

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Splice1138 t1_j7n8hfi wrote

The page I read it on might have been simplifying things, not saying that's exactly how it's implemented. I do know if you play around with subsampling RGB chanels via Photoshop, for example, blue is the least noticeable, red somewhat, green very noticeable.

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