A hilarious question about a photography darkroom on 'Stranger Things' is going viral: 'What is the purpose of this 'red room'?'

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• The latest season of "Stranger Things" debuted on Netflix on July 4, and fans are loving it.
• In the third season, two of the show's characters work at a local newspaper. Given the '80s setting, that newspaper uses a photography darkroom to develop its photos.
• But viewers in 2019 who grew up with smartphones and the internet aren't necessarily aware of what a darkroom is, which resulted in a hilarious - and now viral - question.
• Visit Business Insider's homepage for more stories.

The third season of "Stranger Things" is a delightful re-creation of 1980s smalltown America that's long gone, right down to the Waldenbooks and Sam Goody in the local mall. 

It was a time before smartphones and the internet, before memes and the retail apocalypse. It was a time when photographs still had to be developed by hand in a "darkroom," just like one of the show's main characters has to do repeatedly while working for a local newspaper.

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The darkroom from "Stranger Things."

But let's say you grew up in a world where photography was all handled by a magical supercomputer in your pocket - you might not know what "the purpose of this 'red room' is.

That's exactly what happened with one user posting to the online forum StackExchange in a question that's since gone viral on social media:

Netflix/StackExchange

The "red room," of course, is a darkroom used for developing photos.

But the idea of a "Stranger Things" viewer outright not knowing what such a room is and what it's used for has made some folks feel absurdly old.

Thankfully, folks in the StackExchange forum generously supplied a thorough answer to the use of a darkroom in photography, and why a red light would be used to illuminate such a room.

But just in case you're wondering yourself: Before digital photography, images were developed by hand in chemical baths kept in "darkrooms." Light from the outside could potentially ruin any photos being developed, so a red light (which doesn't interfere with photo development) is often used. 

And for the millions of you who grew up with darkrooms and manually developed photos: Yep, this is where we're at. Just wait until they start asking about cassettes!