Font Typesetting Function 06: “Proportional Metrics”

[Proportional Metrics] in InDesign/Illustrator is a function to narrow the character based on the character width information that fonts have for typesetting with narrowed spacing between characters.

The feature tag is palt for horizontal typesetting, which is a shortened name for “Proportional Alternate Widths.” I read palt as “P aruto.” Some read it as “P ɑ:lt,” which sounds more English. I also heard that some people say “Paruto.” All of these are okay.

The feature tag of proportional metrics for vertical typesetting is vpal (Proportional Alternate Vertical Metrics). I just call it “vpal” without any twist.

The purpose of narrowed spacing between characters by proportional metrics is to artificially achieve proportions similar to Latin by adjusting the side bearing of Kana, etc. designed within the square frame.　If we are dealing with horizontal typesetting, each side bearing on the left and right is independently adjusted. That value is set in advance by the font maker, and stored in the font.

(mm)