Sorry for all the messages; I am exploring things I don't really understand. I hope someone can enlighten me! With the following colour set-up: \setupcolors[rgb=no,cmyk=yes,spot=yes,state=start] \definecolor[PantoneTwoNineFour][c=1,m=.56,y=0,k=.18] \definecolor[IFSbluetabletint][PantoneTwoNineFour][p=.15] and then using this tint as a textbackground and also as a backgroundcolor in frames, I am getting complaints from my printers that black overprinted on the tint is 'knocking out' the tint and leaving white on the separated plate. I have read and re-read the useful msplit.pdf which suggests that the implicit criterium=all will negate this effect, but perhaps I have misunderstood? Two questions: 1. how can I stop black overprinting from knocking out the tint, and 2. is there a way I can check that it is working properly without sending it to the printer each time? Thanks as ever for any help. Do I need to post example output? Duncan