January 9, 1839. Long before cell phone cameras, people took photos using copper and heat. On this date, the French Academy of Sciences announced Louis-Jacques-Mandé Daguerre’s daguerreotype photography process to the world.
Exposure times for early daguerreotypes were typically about 10 minutes, with pictures taken on a sheet of copper that had a coat of silver halide on top. After exposing the sheet to heat, the plate would be treated with substances to bring out the image.
Although painfully slow by today’s standards, the relatively rapid processing time made commercial photography a viable business for the first time. Reports indicate it took only about half an hour to develop images. It used to take hours before that.
Elizabeth Howell is an award-winning Canadian journalist who can't stop talking about space and science. As a teenager, she saw the movie Apollo 13 and wanted to be an astronaut. That hasn't happened - yet - but at least she gets to write about them. Elizabeth's favourite career moments so far include attending three shuttle launches, and legitimately writing the word "snot" into a Mars Curiosity story. Besides EarthSky, you can read Elizabeth's work in SPACE.com, Universe Today, SEN.com, All About Space and other fun places. Elizabeth's space obsession extends to her hobbies; she's a big fan of Battlestar: Galactica and has met all five TV Star Trek captains. She even visited Captain Kirk's future birthplace in small-town Iowa.