Hi Nigel, how about:
\setupoutput[pdftex] \setupcolors[state=start]
\startreusableMPgraphic{bg} StartPage ; z11 = ulcorner Page ; z12 = urcorner Page ; z13 = lrcorner Page ; z14 = llcorner Page ; z91 = (-1, 1.414) ; z92 = ( 1, 1.414) ; z93 = ( 1,-1.414) ; z94 = (-1,-1.414) ; z21 = z11 - 16z91 ; z22 = z12 - 16z92 ; z23 = z13 - 16z93 ; z24 = z14 - 16z94 ; z31 = z21 - 6z91 ; z32 = z22 - 6z92 ; z33 = z23 - 6z93 ; z34 = z24 - 6z94 ; fill z11--z12--z13--z14--z11--z21--z24--z23--z22--z21--cycle withcolor yellow ; fill z21--z22--z32--z31--cycle withcolor .9white ; fill z22--z23--z33--z32--cycle withcolor .8white ; fill z23--z24--z34--z33--cycle withcolor .9white ; fill z24--z21--z31--z34--cycle withcolor .8white ; StopPage ; \stopreusableMPgraphic
\startreusableMPgraphic{bg} StartPage ; fill Page enlarged 1mm withcolor yellow ; % bleed path p ; p := Page enlarged -5mm ; path q ; q := Page enlarged -10mm ; fill q withcolor white ; drawoptions(withcolor red) ; fill reverse topboundary q -- topboundary p -- cycle ; fill reverse bottomboundary q -- bottomboundary p -- cycle ; drawoptions(withcolor green) ; fill reverse leftboundary q -- leftboundary p -- cycle ; fill reverse rightboundary q -- rightboundary p -- cycle ; StopPage ; \stopreusableMPgraphic
\defineoverlay [bg] [\reuseMPgraphic{bg}]
\setupbackgrounds [page] [background={bg}]
\starttext \dorecurse{3}{\input knuth} \stoptext
Hans ------------------------------------------------------------------------- Hans Hagen | PRAGMA ADE | pragma@wxs.nl Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: +31 (0)38 477 53 69 | fax: +31 (0)38 477 53 74 | www.pragma-ade.com ------------------------------------------------------------------------- information: http://www.pragma-ade.com/roadmap.pdf documentation: http://www.pragma-ade.com/showcase.pdf -------------------------------------------------------------------------