#candelas

the worst unit is the candela. the candela is stupid.

what's the candela, you ask? well, it measures the brightness of light

"oh that sounds reasonable" you say, "just measure the energy or power emitted!" nope. they would not do anything nearly so simple. a lightbulb emitting a watt of yellow light is more candelas than a lightbulb emitting a watt of red light.

"ok that's weird" you say, "but maybe they're adjusting for that somehow? maybe it measures number of photons?" again, that would be far too reasonable. a lightbulb emitting a fixed rate of yellow-light photons is more candelas than the same rate of purple-light photons.

but what are they even measuring then? what else is there to measure? clearly they ran out of ideas while making up units, because what they're actually measuring is the SUBJECTIVE BRIGHTNESS OF LIGHT TO THE HUMAN EYE. the candela is STUPID

a reasonable question to ask is: how would you even measure the brightness of light to the human eye? aren't a lot of human eyes different? don't different things look bright in different circumstances? aren't there colorblind people in the world?

surely the General Conference on Weights and Measures, which spent millions precisely calibrating magnetic quantum flux to avoid basing the kilogram on a random block in France, has a clever solution!

no. no they don't. the candela is stupid.

as far as I can tell, what you do is you first measure how much light of each wavelength comes in. Then you multiply each measurement by a "luminosity function", which measures brightness to the human eye:

you will notice that there are multiple functions shown in this diagram. the SI system has five of these, for different lighting conditions. do your lighting conditions not exactly follow one of the Five Official Standardized Lighting Conditions? guess you're out of luck then.

and whose eye are we using? why, the Official Standardized CIE Photometric Observer, of course: the "ideal observer having a relative spectral responsivity that conforms to a CIE-defined spectral luminous efficiency function for human vision"

(and no I can't show you this function because the fine people of the ISO put it BEHIND A PAYWALL. who puts measurements determining a fundamental SI unit BEHIND A PAYWALL. the candela is stupid)

all right, so we're measuring a fundamental unit using a (nonexistent) idealized observer in one of five random lighting conditions. how did they find the values for this? i'm...not entirely sure. but here's a glimpse, based on a few of the most recent studies I found used for this:

"...heterochromatic (minimum) flicker photometric data obtained from 40 observers (35 males, 5 females) of known genotype..."

"To obtain an estimate of the mean L-cone fundamental, we weighted [weird variables] according to the ratio of 0.56 L(S180) to 0.44 L(A180) found in the normal, male Caucasian population...and averaged them together"

that's right, our Official Objective Brightness Unit is probably sexist and racist. none of the other SI units have a chance to be sexist and racist. a meter is a meter in every country on Earth. 6.022*10^23 For Women is still 6.022*10^23. but the candela is-- probably-- the white man's candela, because you can absolutely bet that genetic drift around the world gives different values for this stuff.

thank you for the ask! as decided by tymblr itself, these polls show some of the top internationally known (?) welsh artists. BUT, here are some personal recommendations from yours truly:

Adwaith

an all female post punk indie rock band from carmarthen. their songs are really catchy, cover a range of genres, and satisfy the urge to be serenaded by a choir of angels with electric guitars and synths

Candelas

an anonymous tumblr user told me about candelas recently, and I can't get enough. they're an award-winning rock band from llanuwchllyn, and sing in both welsh and english. if you're gonna listen to any welsh band, listen to them

Catatonia

the myth, the legend, the one and only. they're my mother's favourite band, so listen to them for my mam, please. if you like alternative rock from the post-britpop days of the mid-90s in cardiff, with a front woman who sounds like she smokes 50 packs a day, then you're in luck

International Velvet - Catatonia

Gwahoddiad (Arglwydd Dyma Fi) - Cerys Matthews

Ti - Edward H Dafis (live version)

Pishyn - Edward H Dafis (literally a song about how hot someone is XD)

Ysbryd y Nos - Edward H Dafis 

Cariad, Cariad - Mega YouTube has failed me! :(

Calon Lan - Cerys Matthews (there are other versions, but I love Cerys. XD)

Sosban Fach - DJSG/Alistair James (this is more like a dance remix but it’s amazing!)

Cyfri Geifr - Llangollen Male Voice choir (it needs to be sung in a choir tbh, to get the feel).

Calon - Caryl Parry Jones

Rhedeg i Paris - Candelas

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