Wityh this working example:

\starttext

The quick brown fox jumped over the lazy dog

\definefontfeature

[effect-widen]

[effect={width=.2,delta=0.3}]

\definedfont[Sans*widen,effect-widen]

The quick brown fox jumped over the lazy dog

\stoptext

I am puzzling to turn my working \definedfont into a \definefont so I can use that instead.

Actually, my setup is Optima with Helvetica used for Cyrillic:

\definefallbackfamily

[archimate]

[ss]

[Helvetica]

[preset=range:cyrillic,

tf=style:light,

it=style:lightoblique,

bf=style:regular,

bi=style:oblique,

force=yes,

rscale=1.0]

\definefontfamily [archimate] [ss] [Optima]

\setupbodyfont[archimate]

And I would like the effect to work on just the Optima font (which is a bit light for this use)

I’ve been trying to work out using \definefont with the effect but have so far failed.

Thanks,