How a laser turns a disc track into a picture
A LaserDisc does not store each image as a file of digital pixels. Its spiral track carries a rapidly changing pattern of tiny marks. As the disc spins, a low-power laser shines on the track; a sensor measures changes in the reflected light and turns them into an electrical signal.
That signal encodes an analog video waveform: information varies continuously, much like the signal from a broadcast television system. The player separates and processes the waveform, then sends the resulting video to the television. The laser is therefore a reader, not a beam that paints the picture onto the screen.
Why the distinction mattered
A disc can be read optically without the information on it being digital. On a digital disc, the player interprets patterns as discrete bits and uses them to reconstruct data. LaserDisc’s video instead preserved a continuous signal, so it avoided the blocky artifacts associated with some digital compression but remained vulnerable to picture noise and gradual signal degradation.
The format also paired different kinds of information: video was analog, while some later LaserDiscs included digital audio alongside analog audio tracks. That mix shows why the shiny surface alone cannot tell you whether a medium is analog or digital. What matters is how the player interprets the pattern it reads.
