x-height

Source: Wikipedia, the free encyclopedia.
A diagram showing the line terms used in typography

In typography, the x-height, or corpus size, is the distance between the baseline and the mean line of lowercase letters in a typeface. Typically, this is the height of the letter x in the font (the source of the term), as well as the letters v, w, and z. (Curved letters such as a, c, e, m, n, o, r, s, and u tend to exceed the x-height slightly, due to overshoot; i has a dot that tends to go above x-height.) One of the most important dimensions of a font, x-height defines how high lowercase letters without ascenders are compared to the cap height of uppercase letters.

PT Sans and EB Garamond
. The caption styles both have increased x-heights to make the text clear even printed small. EB Garamond's is also very visibly bolder.
French renaissance typefaces, 1592. The smaller typeface at the bottom has a proportionally higher x-height.[a]

Display typefaces intended to be used at large sizes, such as on signs and posters, vary in x-height. Many have high x-heights to be read clearly from a distance. This, though, is not universal: some display typefaces such as Cochin and Koch-Antiqua intended for publicity uses have low x-heights, to give them a more elegant, delicate appearance, a mannerism that was particularly common in the early twentieth century.[2][3] Many sans-serif designs that are intended for display text have high x-heights, such as Helvetica or, more extremely, Impact.

Extra-small x-height in handwritten (but non-cursive) sign

Design considerations

Medium x-heights are found on fonts intended for body text, allowing more balance and contrast between upper- and

lowercase letters and a brighter page. They then increase again for optical sizes of fonts designed for small print, such as captions, so that they can be clearly read printed small.[4][5]

Some common fonts on one line, comparing their usage and x-heights

High x-heights on display typefaces were particularly common in designs in the 1960s and '70s, when

ITC Garamond.[6][7] More recently, some typefaces such as Mrs Eaves, Neutraface and Brandon Grotesque have been issued with distinctively low x-heights to try to create a more elegant appearance. While computers allow fonts to be printed at any size, professional font designers such as Adobe issue fonts in a range of optical sizes optimized to be printed at different sizes.[8] As an example of this, Mrs Eaves exists in two versions: an original style intended to give an elegant, bright appearance, and a less distinctive 'XL' design intended for body text.[9]

Some research has suggested that while higher x-heights may help with reading smaller text, a very high x-height may be counterproductive, possibly because it becomes harder to identify the shape of a word if every letter is nearly the same height. For the same reason, some sign manuals discourage all-capitals text.[10][11][12]

Use in web design

In

Mozilla Firefox dimensions ex closer to the actual x-height of the font, rounded relative to the font's current pixel
height. Thus, the exact ratio of ex to em can vary by font size within a browser if the determined values are rounded to the nearest whole unit. For example, a browser calculating an x-height of 45% on a font 10 pixels tall may round ex to either 4 pixels or 5 pixels or leave it at 4.5 pixels.

Other important dimensions

Lowercase letters whose height is greater than the x-height either have descenders which extend below the baseline, such as y, g, q, and p, or have ascenders which extend above the x-height, such as l, k, b, and d. The ratio of the x-height to the body height is one of the major characteristics that defines the appearance of a typeface. The height of the capital letters is referred to as cap height. x-height is most important in regular designs, such as most serif and sans-serif designs; script typefaces that mimic irregular handwriting and calligraphy may not have a consistent x-height across all letters.

See also

References

  1. ^ Vervliet 2008, p. 220; Type Specimen Facsimiles, p. 3
  2. ^ "Chaparral® Pro release notes" (PDF). Adobe. Retrieved 5 November 2014.
  3. ^ Tracy, Walter (1986). "Proportion". Letters of Credit. pp. 48–55.
  4. ^ "Optical Size". Adobe. Retrieved 7 November 2014.
  5. ^ Frere-Jones, Tobias. "MicroPlus". Frere-Jones Type. Retrieved 1 December 2015.
  6. ^ Simonson, Mark. "Indiana Jones and the Fonts on the Maps". Retrieved 6 November 2014.
  7. ^ Bierut, Michael. "I Hate ITC Garamond". Design Observer. Retrieved 6 November 2014.
  8. ^ Slimbach & Brady. "Adobe Garamond" (PDF). Adobe. Archived from the original (PDF) on February 23, 2015. Retrieved 6 November 2014.
  9. ^ "Introducing Mrs Eaves XL" (PDF). Emigre. Archived from the original (PDF) on 6 November 2014. Retrieved 6 November 2014.
  10. ^ Bertucci, Andrew. "Sign Legibility Rules of Thumb" (PDF). United States Sign Council. Retrieved 22 June 2015.
  11. ^ Herrman, Ralph (9 April 2012). "Does a large x-height make fonts more legible?". Retrieved 22 June 2015.
  12. ^ Hermann, Ralph (September 2009). "Designing the ultimate wayfinding typeface". Retrieved 22 June 2015.
  1. ^ The name "Petit Canon de Garamond is a mistake; it is actually by Robert Granjon.[1]

External links