The colon is a very useful punctuation mark, but some writers experiment with it in unusual ways.
I just read an article written by Artistic Director Anthony Cimolino in Fanfares, a newsletter of the Stratford Festival. The first two sentences of the article each contain a colon:
I believe that the work we do here at Stratford can be summed up in two words: text and talent. The greatest plays of all time, brought to life by actors who are among the best in the world: that’s the very essence of what we’re here to accomplish.
According to the Oxford English Dictionary, a colon is used “to precede a list of items, or a quotation, or an expansion or explanation.” Perhaps the most common use of a colon is to precede a list. For example, Sally has climbed three of the seven summits: Everest, Kilimanjaro, and Vinson.
In certain instances a colon is used to complete, expand, or explain the words that immediately precede it. In this case the colon acts as a device to focus the reader’s attention. Here’s an example from Robert Frost. In three words I can sum up everything that I’ve learned about life: it goes on.
An important thing to remember about a colon is that it must be preceded by an independent clause. An independent clause is a group of words that can stand on its own as a complete sentence, with a subject and verb.
Let’s look at the first two sentences in the article above. In the first sentence the colon precedes a list, text and talent, and is used correctly.
In the second sentence, the colon is used to expand an idea. However, the colon in this case follows a sentence fragment, not an independent clause. The greatest plays of all time, brought to life by actors who are among the best in the world cannot stand on its own.
Questions of grammar aside, is it a bad sentence? Some might argue that the meaning is clear. But I don’t think it’s as clear as it could be. The odd use of the colon forced me to read the sentence a second time to get the meaning, and you shouldn’t have to read a sentence twice.
I’m a great believer in simple punctuation. Periods and commas do the job in most situations. There is a time and place for colons, but my advice is to use them moderately. Save your imaginative powers for your words, not your punctuation.