Transmitting Photos by Phone

Reading Time: < 1 minute
Recently I watched a 1930s film about how photographs were transmitted by phone. What makes this feature so interesting is that it is explained in a simple to understand manner, using, string that has an image, of all things. This is a clear explanation of how image sending works, but also how television and other technologies would work in year to come.

This is about the analogue sending of an analogue image. The image is scanned, “line by line” and sent via an electric current from the sender to the receiver of the image. On one side the scanner detects whether the image fragment is dark or light and the voltage changes accordingly. This is reflected on the other side to expose the film to reflect the image. Over the space of a few minutes the image gets sent from A to B, to be used in newspapers.

When sending an image as illustrated in the video the process is slow, but with time and technology advances television cameras would do the same thing, but rather than print an image they would send it to a Cathode Ray Tube(CRT) to be printed line by line. As the process sped up to 25 images per second for PAL and NTSC (Never the Same Colour;-) ) so the opportunities increased.

For those with twelve minutes to spare.

100 year of broadcasting.