[Tex/LaTex] How to colour multiple paragraphs

Question

I have a set of commands in my document's preamble that look like this:

\newcommand{\nathaniel}[1]{\textcolor{blue}{[#1]}}
\newcommand{\anotherAuthor}[1]{\textcolor{darkgreen}{[#1]}}

They are to allow my coauthors and I to make comments in the document that will appear in the pdf, to facilitate working on it. However, we find we quite often want to put several paragraphs inside such a comment (e.g. if we've written some new material that we're not sure about, and we want the other authors to notice it). If I try to do this:

\nathaniel{
    one

    two
 }

then I get this error:

paragraph ended before \@textcolor was complete

I know I can use \\ to get a linebreak instead, but I'd prefer it if my custom command would just accept normal paragraph breaks. Is there some command that will cause LaTeX to accept multiple paragraphs as if they were a single one, or some other way to colour multiple paragraphs of text?

Answer 1

\textcolor is similar to \mbox, so it doesn't typeset paragraphs; use the declarative form, instead, in a group:

\newcommand{\nathaniel}[1]{{\leavevmode\color{blue}[#1]}}