fabric colors that were "always" available to common man were shades of everything from red to blue, white, black, brown and grays. purple was also always available, but extremely expensive.

enter coal tar era of chemistry (starting 1840s or so): aniline and later diazo dyes made fabric in all possible colors not only available, but cheap. yes initially they sucked, they ran, they weren't resistant to anything, they will give you ballsack cancer, but they were a thing. for a short time, purple fabric was a choice of the extravagant and the futuristic, and then people just stopped paying attention as it became more common

blue LEDs were sort of also used as a futuristic aesthetic choice, just after they appeared, but before these things became common, and now blue LEDs are just everywhere

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[–] 30 points 11 months ago (2 children)

They are still used where not needed and Way too bright usually. I have more than once used precisely placed electrical tape to reduce them down to a pinhole or slit.

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  • [–] [S] 11 points 11 months ago (1 child)

    blue leds may fuck up your circadian rhytm but won't give you ballsack cancer (probably)

    i heard it's because leds get brighter per mA but circuits don't get updated and leds are fed the same current as 5, 10 years ago

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  • [–] 10 points 11 months ago* (1 child)

    I bought a 22 inch Samsung monitor in 2007 and was annoyed as hell with the extremely bright blue LED under the power button. I never knew untill now why it was there. I just thought it was bad design. I always put something in front of it.

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  • [–] 8 points 11 months ago* (last edited 11 months ago) (1 child)

    Same thing happened to blue dyes. It used to be very expensive, but Prussian Blue being invented in the 18th Century made it show up everywhere cause it used to be so fancy, and then it just became a cheap dye.

    Though the French loved that shit for government official and soldier uniforms, and supposedly that's why cops wear blue

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  • [–] [S] 1 point 11 months ago

    there's indigo and another plant that grows in europe and also makes indigo but less, so you can just farm this thing, unlike purple dye that requires tons of work, and depending on period it was used by commoners (before 1200 or so, in western europe)

    it's a bit funny to look at this today, but woad (that euro indigo) trade was a big deal, it got protected by tariffs and blockades and diplomacy, and all for nothing, ultimately both woad and indigo farming was completely destroyed by synthetic indigo production. indigo wasn't first/easiest dye to make, but it's far from the most complex thing you can cook, even in 1900s. prussian blue is much cheaper than synthetic indigo anyway

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  • [–] 5 points 11 months ago

    It was 2015 10 years ago

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  • [–] 2 points 11 months ago

    Blue LEDs used to be 450nm with narrow fov. Now we're getting them in low 200nm in the UVA, UVB and the very dangerous eye sight blinding UVC.

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