[lltx] Microtypography... now the user asks questions.

[Khaled Hosny]

I think you are best reading Hàn Thế Thành's thesis[1] on pdfTeX's
microtypography which LuaTeX inherited.

And you need not to change the default setup, you can make your own:

\directlua{
  fonts.expansions.setups['myexpansion'] = {
  ...
  }
}
\font\test\lmroman10-regular:expansion=myexpansion at 10 pt

[1] http://www.pragma-ade.com/download-6.htm

Regards,
 Khaled

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer