Setting 'Convert PDF TrueType fonts as Type42' is enabled by default. When this setting is enabled, single-byte TrueType fonts embedded in PDF files are converted into Type42 PostScript fonts. A conversion to Type42 fonts provides the best print quality. When you disable this setting, faulty TrueType font hinting in some fonts (Monotype BookAntiqua-BoldItalic, for example) can be solved.