Fortunately, black Helvetica is not all the formatting Mac OS X Mail can muster.
Use Text Formatting and Images in Mac OS X Mail Signatures
To add colors, text formatting and images to a signature in Mac OS X Mail:
- Select Mail | Preferences... from the menu.
- Go to the Signatures tab.
- Highlight the signature you want to edit.
- Now highlight the text you want to format.
- To assign a font, select Format | Show Fonts from the menu and select the desired font.
- To assign a color, select Format | Show Colors from the menu and click the desired color.
- To make text bold, italic or underlined, select Format | Style from the menu, followed by the desired font style.
- To include an image with your signature, use Spotlight or Finder to locate the desired image, then drag and drop it to the desired location in the signature.
- Go to the Composing tab.
- Make sure Rich Text is selected under Message Format: for formatting to be applied to signatures. With Plain Text enabled, you will get a plain text version of your signature.
For more advanced formatting, compose the signature in a HTML editor and save it as a web page. Open the page in Safari, highlight all and copy. Finally paste into a new signature in Mail. This will not include images, which you can add using the above method.