Have you ever wondered how film cameras expose the date and time the image was captured directly onto the negative? While this little detail might seem like a straightforward process at a cursory glance, the actual implementation is far more interesting than you likely expect.

YouTube channel Applied Science has shared a 14-minute video that details the inner workings of how film cameras impose the date and time onto the film negative. For the video, presenter Ben Krasnow tears apart a seemingly unbranded camera with the model number 'PC620D.'

While the entire video is well worth a watch for all of the interesting tidbits Krasnow finds along the way, the system works by projecting light from a small incandescent bulb through a micro LCD projector, which in turn exposes a small portion of the film negative when the shutter is pressed.

As for the orange/red coloring often associated with the 'stamped' time on a photograph, Krasnow concludes the coloring is due to the light being projected through the film substrate before hitting the silver halide particles, which in turn causes the otherwise white light to have its signature orange glow.