I am perhaps using font typescripts incorrectly. Nevertheless, the recent minimals from the garden appears to have introduced a bug handling rscale. Thanks, Alan Minimal example: \definetypeface [postscript] [rm] [serif] [times] [default] \definetypeface [postscript] [ss] [sans] [helvetica] [default] [rscale=.9] \definetypeface [postscript] [tt] [mono] [courier] [default] [rscale=1.1] \switchtotypeface [postscript] [12pt] \setupbodyfont [sans,12pt] \starttext text \stoptext ! Missing number, treated as zero. <to be read again> . \relativefontsize ->. 9 \dodefinebodyfontnopxx ...umber \relativefontsize }{#2}{#2#1#3#4#5} {\normalu... \next6 #1,->\dodododefinebodyfont {ss}{4pt}{#1} \doprocesscommaitem <argument> \relax tf=Sans sa 1, bf=SansBold sa 1, it=SansItalic sa 1, sl=San... \doprocesscommalist ...aitem \gobbleoneargument #1 ,]\relax \global \advance ... ... l.2 ...] [sans] [helvetica] [default] [rscale=.9]