As he was reviewing the different styles of letter presses used, he went off into an explanatory tangent about the history of typewriters. When Watson returned to the subject at hand, he realized that the type of ribbon made the difference for practically seamless corrections.
This is a correctable film ribbon, which first made an appearance in the Correcting Selectric II in 1973. …This white tape sitting near the ribbon is really just sticky tape, and when you press this key below the keyboard, the type head moves back one space and when you next press a key, it will lift the sticky tape into position instead of the ribbon. …So, the pigment gets yanked right off the paper like nothing ever happened. At least… mostly.
As typewriters became more advanced, so did the correction features.
Since this typewriter is purely mechanical, the correcting feature is fully manual. To undo a mistake, it’s best to hold down the correcting key and then hit the erroneous letter’s key a few times. Usually after the third strike, we have lift-off.