The earliest photographs took an incredibly long time to develop. The first recorded photograph took eight hours to develop. Can you imagine sitting in front of a camera for that long for one photograph? That’s part of why the old Victorian era photos look so grim. No one can hold a smile that long. It took almost 15 years before that exposure time could be cut down. The eight hour development time was common from 1826 to 1839. In 1839, the first camera to develop in fifteen minutes was introduced, and the eight hour development prototype was ditched.
Then came the Polaroids, which developed in mere seconds on the paper once they were out of the camera. Now, we have almost instant development with the invention of the digital camera.