Wireless World 1964 Oscilloscope

[ppppenguin]

The phosphor requirements for professional flying spot scanners are stringent. You need the shortest possible persistence to minimise the need for afterglow correction. You also need fine grain. Not too bad in monochrome where short persistence blue is readily available. Harder for colour where you need enough output across the spectrum to give decent signal to noise ratio. Ideally with the same short persistence across the spectrum.

The decay curve of a phosphor is not a simple exponential. From memory I think the afterglow correctors in a Cintel Mk II scanner had 5 or 6 separate adjustments, each with a different time constant. Replicate this for each of the RGB channels. There was a special slide or film to set them up correctly.