In computer technology, the golden rule for hyphenation of new technology terms is to write them as separate words when they are first coined, as hyphenated words when they are widely used in the technology community, and as monolexemic terms when the terms are widely used by the general population. For example, in the Sixties we had electronic mail, in the Seventies we had e-mail, and around 1993 when the Arpanet was commercialized and renamed to Internet everybody went on email.
This rule is pretty simple to remember. For color compounds the situation is a little sticky, because if changed significantly in the 16th Edition of The Chicago Manual of Style. According to rule 7.85, section 1, under colors (page 375), the new rule is that in the manner of most other such compounds, compound adjectives formed with color words are now hyphenated when they precede a noun. They remain open when they follow the noun.
- emerald-green tie
- reddish-brown flagstone
- blue-green algae
- snow-white dress
- black-and-white print
- his tie is emerald green
- the stone is reddish brown
- the water is blue green
- the clouds are snow white
- the truth is not black and white
While we are at it, rule 7.76 regarding the capitalization of “web” and “Internet” also changed. Chicago now prefers web, website, web page, and so forth—with a lowercase w. But capitalize World Wide Web and Internet.
Since files are now more important than colors, Chicago prefers to present abbreviations for file formats in full capitals. Therefore, write PDF instead of pdf, even when usually we use the latter when we actually specify file names.
More Chicago capitalization examples:
- Macintosh; PC; personal computer
- hypertext transfer protocol (HTTP); a transfer protocol; hypertext
- Internet protocol (IP); the Internet; the net; an intranet
- the Open Source Initiative (the corporation); open-source platforms
- the World Wide Web Consortium; the World Wide Web; the web; a website; a web page
Returning to the opening, although nobody younger than 21 years of age has ever experienced a world without email, on page 380 the over twenty-one-year-old white-haired Chicago people still prefer e-mail and e-book.