This is a dirty hack to change the color of the crop marks and the page number at the corner of a page when \setuplayout[marking=on]. Edit the file: tex/texmf-context/metapost/context/base/mpiv/mp-crop.mpiv in the distribution, changing two lines: ----- (here i'm reproducing only the last part of the file) ------ def page_marks_add_lines(expr width, height, length, offset, nx, ny, boxtoo) = % todo: namespace pickup pencircle scaled 1/2 ; interim linecap := squared ; interim linejoin := butt ; path page ; page := fullsquare xscaled width yscaled height ; path more ; more := page enlarged (offset+length/2,offset+length/2) ; % draw crop_marks_lines(page,length,offset,nx,ny,boxtoo) ; draw crop_marks_lines(page,length,offset,nx,ny,boxtoo) withcolor (0,0,0,1) ; setbounds currentpicture to page ; enddef ; def page_marks_add_number(expr width, height, length, offset, n) = % todo: namespace pickup pencircle scaled 1/2 ; interim linecap := squared ; interim linejoin := butt ; path page ; page := fullsquare xscaled width yscaled height ; path more ; more := page enlarged (offset+length/2,offset+length/2) ; for s=llcorner more, lrcorner more, ulcorner more, urcorner more : % draw textext(decimal n) shifted s ; draw textext(decimal n) shifted s withcolor (0,0,0,1) ; endfor ; setbounds currentpicture to page ; enddef ; ----------------------------------------------------------- You must add "withcolor (0,0,0,1)" before the final semicolon to two lines: the ones that i commented out with a leading "%". In case you wanted crop marks in all the CMYK channels, add "withcolor (1,1,1,1)". Once you modify the file, remake the format with context --make A parametric solution would let you define a "registration" color in ConTeXt, then map it to the corresponding "withcolor" instruction in mp-crop.mkiv. I'm sure there are already functions to do that mapping. It's the difficult part (at least for me) when Hans talks about adding "some control over these cropmark colors by using symbolic names". Massi