So, it is interesting and more complicated. The exact part:<div><br></div><div><div>\setupbackend</div><div>   [format=PDF/X-1a:2001,</div><div>    intent=Coated FOGRA39 (ISO 12647-2:2004),</div><div>    option=always,% for a much bigger document :-)</div>
<div>   ]</div></div><div><br></div><div>… seems to work on my Debian standalone ConTeXt installation (ok, I will test it again but it objected nothing (about ICC not embedded) in yesteday in Acrobat&#39;s preflight) but on my Win XP standalone one it doesn&#39;t work. I have the profiles in the same directories, of course. On Win it can&#39;t eat the comma, on Debian it can.</div>
<div><br></div><div>Although the advice:</div><div><br></div><div>\definecolor[cmykblack][k=1]</div><div>\setupcolors[rgb=no,cmyk=yes,intent=overprint,textcolor=cmykblack]</div><div><br></div><div>… seems very logical, it doesn&#39;t work, preflight still sees the text like a greyscale.</div>
<div><br></div><div>Thanks, Honza</div>