Hello Andrés! On Wed, 11 Nov 2020 at 01:25, Andres Conrado Montoya Acosta < elandi@chiquitico.org> wrote:

may I ask someone, who understands knockout and overprint in the printing

...

press, to check test cases in the attached file from the test suite, if overprint is working or not in Mark IV, please?

Regards, Jano

Hi Jano, as far as I can check with my pdf editors, it seems overprinting is working. The black ink is printed above the blue, with no white reserve below it.

Sorry for the delay, I had to downsample the screenshots after the original reply didn't get through (too big) and in the end remove them completely. Thank you for checking. Looks like a bug in Acrobat (older version 11.0.23), not ConTeXt. What editors do you use? After your test I was digging deeper. When I disable black plate in *Preview: Separations* it doesn't show an overprint, the room under the letters is white (original problem). When I remove one overprint manually in Illustrator, Acrobat shows the remaining overprints. I've found out later, I could use *Profile: Color Warnings*, where all overprints are visible, but I would rather see it in separated plates. Hope this helps someone in the future, too. Jano