<P> A variation known as "Correcting Selectrics" introduced a correction feature, where a sticky tape in front of the carbon film ribbon could remove the black - powdered image of a typed character, eliminating the need for little bottles of white dab - on correction fluid and for hard erasers that could tear the paper . These machines also introduced selectable "pitch" so that the typewriter could be switched between pica type (10 characters per inch) and elite type (12 per inch), even within one document . Even so, all Selectrics were monospaced--each character and letterspace was allotted the same width on the page, from a capital "W" to a period . Although IBM had produced a successful typebar - based machine with five levels of proportional spacing, called the IBM Executive, proportional spacing was not provided with the Selectric typewriter or its successors the Selectric II and Selectric III . </P> <P> The only fully electromechanical Selectric Typewriter with fully proportional spacing and which used a Selectric type element was the expensive Selectric Composer, which was capable of right - margin justification and was considered a typesetting machine rather than a typewriter . </P> <P> In addition to its electronic successors, the Magnetic Tape Selectric Composer (MT / SC), the Mag Card Selectric Composer, and the Electronic Selectric Composer, IBM also made electronic typewriters with proportional spacing using the Selectric element that were considered typewriters or word processors instead of typesetting machines . </P> <P> The first of these was the relatively obscure Mag Card Executive, which used 88 - character elements . Later, some of the same typestyles used for it were used on the 96 - character elements used on the IBM Electronic Typewriter 50 and the later models 65 and 85 . </P>

What did the invention of the typewriter lead to