# Pyrotechnics and Other Curiosities

* Pyrotechnics
* Eidophor Projector

### Pyrotechnics

Pyrotechnics could easily be considered as a precursor to modern digital display technology for large scale displays. [See my deep dive here](https://laserpilot.medium.com/pyrotechnics-and-digital-spectacle-12bcbc5e4137)

![A "living firework" with a bunch of lit up pixels as a precursor to LED's](/files/S7cns4IBk2CYY70UjZgx)

![A large pyrotechnic display showing faces lit up in light.](/files/67xAAegpoYZKPxB35d3D)

### Eidophor Projector

![](/files/FC9esRFPQ91ovTlSWBx9)

​[Wikipedia page](https://en.wikipedia.org/wiki/Eidophor)​

> Eidophors used an optical system somewhat similar to a conventional [movie projector](https://en.wikipedia.org/wiki/Movie_projector), but substituted a slowly rotating mirrored disk or dish for the film. The disk was covered with a thin film of transparent high-viscosity oil, and through the use of a scanned [electron](https://en.wikipedia.org/wiki/Electron) beam, electrostatic charges could be deposited onto the oil, causing its surface to deform. Light was shone on the disc by a striped mirror consisting of strips of reflective material alternating with transparent non-reflective areas. Areas of the oil unaffected by the electron beam would allow the light to be reflected directly back to the mirror and towards the light source, whereas light passing through deformed areas would be displaced and would pass through the adjacent transparent areas and onwards through the projection system. As the disk rotated, a [doctor blade](https://en.wikipedia.org/wiki/Doctor_blade) discharged and smoothed the ripples in the oil, readying it for re-use on another television frame.[\[10](https://en.wikipedia.org/wiki/Eidophor#cite_note-Ba-10)]The Eidophor was a large and cumbersome device and not commonly used until there was a need for good-quality large-screen projection. This opportunity arose as part of the [NASA](https://en.wikipedia.org/wiki/NASA) space program, where the technology was deployed in mission control.

![How an Eidophor Projector works](/files/ya0wFxOpTP3EovXTaQAb)

{% embed url="<https://youtu.be/3-BvMcqEc98>" %}


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