I would like to do something like:
\setuphead[section][before={\blank[1.5*big] \testpage[12]}]

This does not work. I get:
to be read again>
                   *
<argument> 1.5*
               big
\addaskedblankskip ...nce \blankskip #1\dimexpr #2
                                                  \relax

But I can do:
\setuphead[section][before={\blank[2*big] \testpage[12]}]

How to implement what I want?

-- 
Cecil Westerhof