All caps

In typography, all caps (short for 'all capitals') refers to text or a font in which all letters are capital letters, for example: Text in All Caps. 'All caps' may be used for emphasis (for a word or phrase). They are commonly seen in legal documents, the titles on book covers, in advertisements and in newspaper headlines. Short strings of words in capital letters appear bolder and 'louder' than mixed case, and this is sometimes referred to as 'screaming' or 'shouting'. All caps can also be used to indicate that a given word is an acronym. Studies have been conducted on the readability and legibility of all caps text. Scientific testing from the 20th century onwards has generally indicated that all caps text is less legible and readable than lower-case text. In addition, switching to all caps may make text appear hectoring and obnoxious for cultural reasons, since all-capitals is often used in transcribed speech to indicate that the speaker is shouting. All-caps text is common in comic books, as well as on older teleprinter and radio transmission systems, which often do not indicate letter case at all. In professional documents, a commonly preferred alternative to all caps text is the use of small caps to emphasise key names or acronyms (for example, .mw-parser-output .smallcaps{font-variant:small-caps}Text in Small Caps), or the use of italics or (more rarely) bold. In addition, if all caps must be used it is customary to slightly widen the spacing between the letters, by around 10% of the point height. This practice is known as tracking or letterspacing. Some digital fonts contain alternative spacing metrics for this purpose. Messages typed completely in capital letters are often equated on social media to shouting and other impolite or argumentative behaviors. This became a mainstream interpretation with the advent of networked computers, from the 1980s onward. However, a similar interpretation was already evidenced by written sources that predated the computing era, in some cases by at least a century, and the textual display of shouting or emphasis online was still not a settled matter by 1984. The following sources may be relevant to the history of all caps: Before the development of lower-case letters in the 8th century, texts in the Latin alphabet were written in a single case, which is now considered to be capital letters. Text in all caps is not widely used in body copy. The major exception to this is the so-called fine print in legal documents. Capital letters have been widely used in printed headlines from the early days of newspapers until the 1950s. In the 1990s, more than three-quarters of newspapers in the western world used lower-case letters in headline text. Discussion regarding the use of all caps for headlines centers on the greater emphasis offered by all caps versus the greater legibility offered by lower-case letters. Colin Wheildon conducted a scientific study with 224 readers who analyzed various headline styles and concluded that 'Headlines set in capital letters are significantly less legible than those set in lower case.' All caps typography was common on teletype machines, such as those used by police departments, news, and the then-called Weather Bureau, as well as early computers, such as certain early Apple II models and the ZX81, which had a limited support for lower-case text. This changed as full support of ASCII became standard, allowing lower-case characters. With the advent of the bulletin board system, or BBS, and later the Internet, typing messages in all caps commonly became closely identified with 'shouting' or attention-seeking behavior, and may be considered rude. Its equivalence to shouting traces back to at least 1984 and before the Internet, back to printed typography usage of all capitals to mean shouting. (The convention may have predated the Internet, and existed in print for many years before, however — see above).