I came across an OpenType font with TrueType outline that had an .otf extension, attempting to use it gave me this error: !luaTeX error (file /home/khaled/.fonts/UthmanTN1_Ver06.otf): can't find table `CFF ' ==> Fatal error occurred, no output PDF file produced! Reading OpenType specification, I see that it allows this: * In all cases, fonts with only CFF data (no TrueType outlines) always have an .OTF extension. * Fonts containing TrueType outlines may have either .OTF or .TTF, depending on the desire for backward compatibility on older systems or with previous versions of the font. TrueType Collection fonts should have a .TTC extension whether or not the fonts have OpenType layout tables present. I'm not sure if this is a LuaTeX of ConTeXt issue, but my guess is that a ConTeXt issue, thus reported here. Regards, Khaled -- Khaled Hosny Arabic localizer and member of Arabeyes.org team