I believe that the automatic color would be black and that is usually the
default color in all of office for new emails, documents, etc. On our email
we have everyone set up so that the font color for all emails (new, reply,
forward) are different shades of blue. But if I wanted to change mine to
black for 1 email, I would choose automatic and not have to look for it in
the 2 rows of colors below it.