Hi,

\setupcolors[state=start]

\setupcolor[rgb]
\setupcolor[xwi]
\setupcolor[ema]

\starttext

\midaligned{\tfb \bf RGB colors}
\blank[3*big]
\showcolor[rgb]
\page

\midaligned{\tfb \bf XWI colors}
\blank[3*big]
\showcolor[xwi]
\page

\midaligned{\tfb \bf EMA colors}
\blank[3*big]
\showcolor[ema]

\stoptext