Help for newbie with colour plates

[Vshra]

Hi all.

I'm doing a booklet using Affinity Publisher (which I love, I have to say!) and exporting it as a PDF. It's a black and white text (the colour book cover is a separate file which isn't an issue here). The company who are working with me to publish it gave me the following message:

I’ve just done an output preview on your text file and it is showing up on all the colour plates. It should just be on the black plate. Please can you change that so the text file is only on the black plate? Your text is showing on all CMYK plates.

I have tried exporting it as greyscale but it's not made a difference. How do I fix this? As a relative newbie, I can't quite see what to do, and would really appreciate some help...

I am using Affinity v1. Enclosed is a screenshot of the main part of my export settings.

Thanks in advance!

[Old Bruce]

Most likely you have a Rich Black instead of just CMYK 0, 0, 0, 100 for the colour of the text. rich black is made with all four inks. Make a colour swatch and have it be 0, 0, 0, 100 in CMYK and assign that swatch to the Colour for the text in the Paragraph Styles.

Myself I think that what is happening is that Greyscale is treated as RGB for the purposes of translating into CMYK.