IBM Plex Sans JP is bigger than other Plex Sans fonts

[plastic041]

IBM Plex Sans JP slightly bigger(or not hinted properly?) than other fonts.

All texts are styled with font-size: 20px;
fonts used in image above are:

• hinted truetype IBM Plex Sans JP
• hinted truetype IBM Plex Sans KR
• truetype IBM Plex Sans
• hinted truetype IBM Plex Sans Arabic
• hinted truetype IBM Plex Sans Hebrew
• hinted truetype IBM Plex Sans Devanagari

[BoldMonday]

This is intentional – all Latin glyphs in Plex Sans JP have been scaled to 105% to mix better with the Japanese character set.

[johnnyshields]

@BoldMonday that's really not ideal; makes it much harder to work with bilingual content. KR and JP glyphs should be the same size... do you have examples of other fonts such as Noto doing this?

[BoldMonday]

@johnnyshields I cannot comment on any specifics since we did not make the decision. The scaling was proposed by the Plex Sans JP designers at Sandoll. I assume they considered mixing Hangul with Japanese but I leave this up to them to answer.

[johnnyshields]

Oddly enough Noto Sans CJK JP (and other CJK) appears to use different alphabet glyphs but they aren't significantly larger.

Noto CJK does also have a larger line height, which is identical between Noto JP and KR.

Based on this I would suggest:

• Use same size alphabet glyphs in all fonts. (If you absolutely must make Plex JP larger, then Plex KR should be too.)
• Use identical line height for JP / KR / SC / TC. (Plex KR seems to have slightly taller line height than JP)

This may all seem pedantic but it's this attention to detail which led us to use Plex in the first place.

[plastic041]

Sorry, closed by mistake.

Use same size alphabet glyphs in all fonts.

I agree. It's difficult to use fonts with partially different glyph sizes.

How about a merged font option like Noto sans CJK?

[Buernia]

The Latin glyphs in Noto Sans CJK are from Source Sans, they’re also larger than the original Source Sans.

[johnnyshields]

How about an merged font option like Noto sans CJK?

Will raise this as a separate ticket

[BoldMonday]

This may all seem pedantic but it's this attention to detail which led us to use Plex in the first place.

@johnnyshields But this very matter is all about attention to detail. The Plex project team looked at multiple tests of Japanese mixed with Latin, where the latter was scaled in different percentages. The team wanted to guarantee that all glyphs contained in Plex Sans JP were perfectly proportioned with each other. Several scenarios were considered including change of UPM, and vertical proportions of Japanese glyphs.

The decision to scale all Latin glyphs was not taken light-heartly and it took significant effort to check and correct all outlines that had rounding errors after scaling. All these glyphs were then hinted again as well. It was the main reason why the release of the JP fonts were delayed.

[johnnyshields]

It was the main reason why the release of the JP fonts were delayed

🤦 This is really unfortunate there was not more community consultation. We had no idea why there was a delay and I get the sense that if this was put to a vote among actual JP users very few would want alphabet to be 105% scaled.

[johnnyshields]

@BoldMonday I'd like to make sure we're not talking cross purposes. Japanese charsets do include full-width (全角) alphabet chars:

Normal: ABCDEFG
Full-Width: ＡＢＣＤＥＦＧ

Is it possible Sandoll commented to 105% scale these chars specifically?

[BoldMonday]

@johnnyshields No there is no mix-up. Sandoll made all proofs and modifications to the Latin glyphs themselves. Here is an example how the project team tested Latin with Japanese:

As you can see vertical typesetting was considered as well.

[johnnyshields]

Therein lies another problem. Alphabet characters are typically written upright when Japanese is written vertically, for example the Nikkei newspaper or magazines. Although both ways are possible, upright alphabet feels more common.