Font Typesetting Function 07: “Various Things About Kerning”

Kerning is used to adjust the spacing between specific characters. Options in the Kerning Menu in InDesign/Illustrator include: Japanese Fixed-Width, Metrics (“Auto” depending on the version of Illustrator), Optical, and Value Specified (Manual).

Settings for Japanese fixed-width are for solid typesetting. Even in case of solid typesetting, many want kerning to be effective and used in Latin. Looking at the example of kerning 0 at the top of the figure, I’m concerned about the spacing between “Y” and “o.” Settings to turn on only kerning for Latin without narrowing the spacing for Japanese is Japanese fixed-width. Kerning for Latin in Japanese fixed-width is the later mentioned metrics kerning.

Metrics is kerning based on the information inside the font set in advance by the font maker. I will talk in more detail about metrics kerning in the next entry.

Optical is kerning based on the algorithm installed in the application software. The kerning information inside the font is not referred to. As seen at the bottom of the figure, tightly narrowed spacing between “a” and “で” is special to optical. In optical, the font that does not have the kerning information can be narrowed. However, it cannot be used for vertical typesetting in Japanese.

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