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I learned about the arc lamp when I was a kid, watching Connections on PBS. John Burke explains it in one episode, and it appears during the title sequence of every episode. IIRC, it was invented to replace theater stage lights, where previously were lit by oil lamps, that had a tendency to start the set on fire.
Here it is : https://archive.org/details/ConnectionsByJamesBurke/Connections/Season+3/Connections+S03E03+-+Drop+the+Apple.mp4
Correction on the use of oil lamps on theatre stages: They used limelights, like where the expression "in the limelight" comes from. They didn't burn oil, they concentrated hydrogen and oxygen into a flame.
Just went down a rabbit hole with that, ended up learning about Australia's Limelight division which created the first multicamera recording in 1901 https://en.wikipedia.org/wiki/Inauguration_of_the_Commonwealth?wprov=sfla1
Yup. The TL;DR is that the flame doesn’t really produce that much light. Instead, it heats limestone, which glows a bright white-amber.
It’s also where the term “upstaging” comes from. The back of the stage is upstage, from when stages used to be heavily sloped (so audiences on the floor could see the performers in the back). Jealous performers would sometimes fight over who could be in the limelight. Since the limelights were spread across the front edge of the stage, the closer you were to the front of the stage (downstage), the brighter you were. So if you were trying to be noticed, you would move downstage (putting the other performers upstage of yourself). By moving closer to the limelights, you would upstage the other performers.
This took on a second meaning though. When you took a performer’s limelight away, they could force you to turn your back on the audience (which is a big no-no in theatre, because you can’t express things with the back of your head, and audiences can’t hear you when you’re facing away from them) by interacting with you. An improvised conversation, for example. By forcing you to turn around, (and by drawing attention towards themselves), they were upstaging your performance. Literally taking your performance and directing it upstage instead of towards the audience.
Finally, limelights were also part of the reason why theatre was so popular with the masses. When performers fought over the limelight, while dressed in their delicate lace and linen costumes, there was a very good chance that one of them would get too close to the limelight. And you know what is really fucking flammable? Lace and linen. When you bought a ticket to the theatre, there was a non-zero chance that you were going to get to watch a lady abruptly disrobe on stage when her skirt hem lit on fire. In an era where seeing an ankle was scandalous, an actress catching on fire would be something that you’d remember for the rest of your life.
It is really sad what is happening PBS kids after Trump cut all of their funding.
Making the masses dumber so they continue to vote for things not in their best interests is part of Trump's platform.
They made fun of airing sesame street in middle eastern countries, but if you think about it...really think about it l...Sesame Street is like some of the best western propaganda out there, and was being placed in front of young children and their mothers (who themselves were likely obedient/subservient to their husbands).
Like, really, there's no better counterterrorism than wholesome propaganda for kids.
I learned about these from the projectionist where I worked, back when I was a kid. When they'd get taken out of a projector and thrown in the garbage, he'd smash them on the ground to get the tungsten electrodes out. Apparently they both looked cool, like the surface of the moon, and sold for a lot!
Ineffably magnificent...
The following lamp looks like creating a whole... Universe...:
- https://en.wikipedia.org/wiki/File:Xenon_Flash_Wiki.ogv (High-speed, slow-motion video of a xenon flashtube recorded at a speed of 44,025 frames per second...)
TIL about the .ogg video format. And mpv for Android is great.
These things have very high CRI, 98 to 100, and are conveniently 6000k. They were used in movie theatres!
Also in stage spotlights. Old follow spots used these, because the huge output made them fantastic for throwing a beam long distances. And the good CRI made performers look really good, and meant it could be colored (like with lighting gels) very well.
Fun fact- The xenon bulbs used in continuous lighting such as projectors and followspots are pressurized at several atmospheres. Common safety measures when changing those bulbs out involve a kevlar suit and face shield reminiscent of a bomb squad suit.
Yup, and the sheer size of a projector is because 90% is shielding in case of a lamp explosion. The actual functional circuitry is about the size of a pi.
The lamps also come in cages.
How much power would I need to pump into a regular incandescent lightbulb with a broken filament to turn it into an arc light?
The electrodes in the base of the bulb are likely to arc over long before that happens, but ignoring that; In the area of 100k volts.
I worked with one in the 80s to do large-format B&W jewelry photography. After a few hours of work, I had a sunburn on one side of my face.
They emmit large parts of the smaller EM spectrum. So, yes.
Like arc welding.