To suppress only the face attribute in <font> tags:
[HTMLOptions] ;UseFontFace = Yes (default, allow face attribute in <font>) or No UseFontFace = No
Allowing <font> tags for size but not for face avoids interfering with CSS specifications. For example, omitting the face attribute is required for W3C validation of HTML 3.2 for JavaHelp; see §20.3.8 Coping with JavaHelp / Oracle Help viewer limitations.
On the other hand, if you use non-Unicode-compliant fonts such as Webdings and Wingdings, the only way to get certain non-Microsoft browsers to render characters in those fonts is to use the face attribute; see §30.5.4 Accommodating browser font-rendering differences.