Font Size and Its Units
字級‧字大小‧字重要性

數位出版設計:意涵/樣式實作-知識美學/數位美學之建構方法

字級/字大小：表現重要性

字級有分中文單位，與英文與網路單位不同系統，而英文與網路單位已趨向相同。

字級中文單位

號中華單位，至今幾已消失。

級：2.5cm=100級，日本單位，至今也近消失。

P：1 in=72P 歐美「印刷時代」單位，新譯「點」，舊譯「皮卡」。

px；像素基本單位，網路時代單位。

Font Size Units 字級/字大小英文/網路單位

It affects the readability that you do not want the size too small.

It also determines the importance of your messages.

字級大小單位分作絕對大小、和相對大小2類單位。

Absolute Units 絕對字級/字大小單位

Points (pt)

Points (pt) 新譯「點」，舊譯「皮卡」。

這是歐美「印刷時代」單位，延用至今，是一般文書、數位出版軟體的預設單位。

pt 的「點」是一種人為規定的「點」，和 px 像素實為真實的「點」，要避免混淆。

1 in=72 pt, an absolute measurement. Points are traditionally used in print media (anything that is to be printed on paper, etc.). Points are fixed-size units and cannot scale in size.

Pixels (px) 像素

Pixels (px) 像素，是設計網路字級/字大小的最佳單位。

Pixels are fixed-size units that are used in screen media (i.e. to be read on the computer screen). One pixel is equal to one dot on the computer screen (the smallest division of your screen』s resolution). Many web designers use pixel units in web documents in order to produce a pixel-perfect representation of their site as it is rendered in the browser. One problem with the pixel unit is that it does not scale upward for visually-impaired readers or downward to fit mobile devices.

Relative Units 相對字級/字大小單位

Relative Units 相對字級/字大小單位，一般只用在網路設計的字級/字大小單位。

早期瀏覽器本身不能調整大小時，是提高「可閱讀性」的設計方法，但會改變設計者的平面設計。

後來瀏覽器本身均能調整大小時，為保留設計者的平面設計，已不建議使用這種單位。

近年，對專為行動裝置，如平板、手機設計的網頁，受到螢幕較小的限制，「輕量網站設計」（也有譯為響應式網站設計），則又必須使用相對字級。

Default relative properties

預設相對字級/字大小單位，以形容詞為單位。

xx-small, x-small, small, medium, large, x-large, xx-large

Percent (%)

百分比相對字級/字大小單位，以12pt = 100% 為基礎計算。

The percent unit is much like the 「em」 unit, save for a few fundamental differences. First and foremost, the current font-size is equal to 100% (i.e. 12pt = 100%). While using the percent unit, your text remains fully scalable for mobile devices and for accessibility.

「Ems」 (em)

動態相對字級/字大小單位，以預設單位 = 100% 為基礎計算。

The 「em」 is a scalable unit that is used in web document media. An em is equal to the current font-size, for instance, if the font-size of the document is 12pt, 1em is equal to 12pt. Ems are scalable in nature, so 2em would equal 24pt, .5em would equal 60pt, etc.

Ems are becoming increasingly popular in mobile documents due to scalability and their mobile-device-friendly nature.