Computer displays can be read remotely by their RF emissions. At least it was possible with CRT displays. Not sure if LCD displays have this characteristic.
It is easier to tell what a typist is typing from their audio signature than it is to TEMPEST a monitor, especially now with modern EMC requirements cutting down the usable signal.
Some people used to have "low emission fonts"; fuzzy edges in very low contrast.
Anyone care to process this clip? I might even have the 'plain text' around somewhere.
On a serious note; I used to get about 5 carbons max on a mechanical office typewriter years go using 'onion skin' paper.
Photocopiers mostly use scanners these days? Back to square one?
Any attempts at picking up audio|electronic emanations will be foiled by traditional TEMPEST type protection.
Typewriter ribbons can be dealt with by old fashioned incineration.
The only way to acquire a signal would be by infiltration of the facility housing the targeted systems.