Yesterday I talked about how the text preceding a colon must constitute a complete sentence. Today I have another colon rule for you. Do you know if you should capitalize or lowercase the first word following a colon? It actually depends.
If you’re following the Chicago Manual of Style (CMoS), the first word following the colon is lowercase unless it is a proper noun or the text following the colon is a question. Furthermore, if a colon is introducing two or more sentences or is introducing speech in dialogue or a quotation, you should also capitalize that first word directly following the colon.
If you’re following AP style guidelines, you should capitalize the first word following the colon if it is a proper noun or the start of a complete sentence.
I hope this information on colons proves helpful to any writers, editors, and proofreaders out there.