There are some terms in typography that are frequently confused with others because they are related in meaning – but still different. Legibility and readability are two of them. These terms are important for designers to know as they contribute to the language used to talk about fonts, typesetting, and design. Legibility and readability both relate to the ease and clarity with which one reads any particular setting of type, but they actually refer to two different concepts: legibility is related to the design of the typeface and the shape of the glyphs, while readability refers to how the font is arranged, or typeset. Both are particularly important when setting text or any smaller type sizes.
The legibility of a typeface is a product of its design, and relates to the ability to distinguish one glyph from another when reading. Factors contributing to a typeface’s legibility include the following:
x-height: This term refers to the height of the lowercase in proportion to the caps. The taller the x-height, the more legible the typeface tends to be.
Character width: The easiest type designs to read are those that have an ‘average’ overall width. Very condensed as well as extended designs are less legible, especially for smaller settings such as text, subheads, and credits.
Weight: Extremely light and heavy weights are more difficult to read, so if legibility is your goal, stick to something in the middle. Book weights (also called Regular) are so named as they are most often used to typeset books for that very reason.
Design traits: The overall shapes and design traits of a typeface, if too quirky or fussy, will reduce legibility. While this might be acceptable for shorter display settings, stick to simpler typeface designs for lengthy text settings.
Stroke contrast: Extreme stroke contrast, that is, the ration of thick to thin strokes, can reduce legibility as well. This is especially true of modern designs such as Bodoni and Didot whose thin strokes can appear so thin when reproduced in print or on the web that it can become challenging to read when used too small or for lots of text.
Counters: The smaller the counters (enclosed or semi-enclosed negative shapes) of a typeface, the more challenging it can be to read. This is a factor when using very heavy weights, and it’s made even worse in smaller settings. Avoid this by knowing ahead of time how a particular typeface looks at the intended size and medium.
Serifs or lack thereof: While serifs are generally believed to enhance legibility, this is not always the case. All of the above factors contribute more to legibility than the serifs: a sans serif design with neutral features can be more legible than some serif typefaces. In addition, it is believed by many professionals that what you read most, you read best. Therefore, in the U.S. where running text in books, magazines, and newspapers are typeset using serif text fonts, readers are most comfortable and familiar with reading serif fonts, and therefore can be more legible to these readers. In countries where sans serifs are more commonly used, they might appear more legible to this audience.
Keep in mind that that not all typefaces are designed to be legible. This is more of a consideration for text designs where the degree of legibility relates directly to holding the reader’s attention for the length of the copy. Display designs are generally used for a fewer words in larger sizes where the objective is to attract a reader’s eye and to convey a mood, feeling, or message, so legibility might not of primary consideration.
Readability is related to how the type is arranged, or typeset, and therefore is controlled by the designer. Factors affecting type’s readability include:
Type size: When setting text, the smaller the size, the more challenging it can be to read. This is especially true for seniors, children, and those with visual impairments. For these reasons, the demographics of your intended audience should be taken into consideration when deciding on a size for text.
Type case: All cap settings for lengthy text are more challenging to read due to the lack of ascenders and descenders which contribute to character recognition, so stick to upper and lowercase when readability is of prime importance.
Line spacing (aka leading): Tight line spacing impacts readability negatively. The amount needed to improve readability will depend on the size and design of a typeface as well as its x-height. Therefore, when ease of reading is of high importance, make sure there is enough line spacing to maximize readability, which in general is at least two to three points for print, and a bit more for smaller digital devices.
Line length: When the line length, or column width, is too short, it can have many hyphenated words, which reduce readability. In addition, the eyes have to make many ‘returns’ that can cause fatigue and reduce comprehension. On the other hand, very long lines can cause confusion when shifting from the end of one line to the beginning of another. For best readability, stick to ‘average’ line length, which is usually between 45 and 70 characters.
Color, or contrast: Make sure there is enough color contrast between the type and its background, lest it becomes harder to read. This is important whether you are using black and white (and tints of the former) as well as color. When styling type for digital usage, be sure to allow for variation from one device, platform, and settings to another, as they can vary dramatically in how they display color and contrast.Tags