Kristi wrote to ask about punctuating captions. She was told that there should never be any punctuation at all in photo captions. She asked about a caption something like this:
Drivers Bill Long and Joy Rae Craig log on to the new system.
Kristi's caption needs a period (full stop) at the end because it's a sentence.
If she had written just a phrase or clause, she would need no period:
Drivers Bill Long and Joy Rae Craig logging on to the new system
If she has several photos with captions–some sentences and some not–she should be consistent and use periods at the end of all of them. (These rules are according to The Chicago Manual of Style; the Microsoft Manual of Style agrees.)
But Kristi wondered if there should be any punctuation at all in captions. To answer her question, let's look at this example with no punctuation:
Drivers from left to right Bill Long Joy Rae Craig Delia Smith and Hugo Washington log on to the new system
If we don't want to drive our readers crazy, we have to punctuate:
Drivers (from left to right) Bill Long, Joy Rae Craig, Delia Smith, and Hugo Washington log on to the new system.
The comma after Smith is optional.
While we are talking about commas, should there be a comma after drivers in Kristi's examples? No. We need to know which drivers, so no comma. However, the sentence below needs commas because the drivers' names are considered extra information.
Our two newest drivers, Bill Long and Joy Rae Craig, log on to the new system.
We already know they are the two newest, so their names are not necessary even though we want to include them. The rule is to use commas to set off extra information that interrupts the flow of the sentence.
Now that I have been writing about captions for Kristi, I will be examining the next few captions I read. Why don't you do so too?