On Mon, 2011-12-05 at 07:33 +0100, W P Blatchley wrote: There is a substitution table which maps from Unicode codepoint to a font containing the glyph (or none, if no fonts contain an appropriate glyph). The table is populated at startup, and remains constant thereafter. No, it doesn't. It *will* match styles/weight when selecting the appropriate initial font, but the substitution table is built without paying attention to this information. As RISC OS fonts carry little metadata about styles/weights, RUfl simply uses the font name as a guide. J.