Directory fonts/cm/mf_optimized_kerning

The files are modified versions of the METAFONT source files
with the corresponding name.
Modifications concern optimized values for character kerning.
They have been evaluated with high resolution (> 1000 dpi) fonts.
For further modifications take care, not to try to correct rounding
errors at - say - 300 dpi at this place. 
Emphasis has been put onto character pairs that are most 
frequent in the English and the German language.
Fonts without serifs have been widely ignored.

IMPORTANT NOTE from the CTAN maintainers:

As these files are changed versions of Donald E. Knuth's original CM source
files, we decided to change the names.

Using these files to create fonts from the Computer Modern source files
without changing the names of the created fonts is a violation of
Donald Knuth's stipulation on the copyright page of Computers & Typesetting,
Volume E and therefore strictly forbidden.

With this changes, the fonts produce quite different results on different 
computer systems, and they will also cause TeX to typeset your old papers 
with different line breaks, page breaks, overfull boxes, etc.