Colour space problem

[Fast Fox]

I have a photobook which is going to be sent to the publisher/printer as a CMYK PDF (Fogra 39)

I have the file setup with the colour space of CMYK/8. I have been converting my colour images to CMYK in photoshop and placing them in the document with no problems. However I am having significant issues with the B&W images which I was advised by the printers to change to Greyscale.

I converted these images to Greyscale in Photoshop and they look fine on the PC.

However when I place them in the Affinity document they suddenly became washed out. It seems some further conversion is taking place. 

I have noticed that if I change the setup/colour to RGB there is no colour change to the greyscale.

Am I doing something wrong or should I be editing in RGB rather than CMYK?

 

[DWright]

Can you please confirm which of the Affinity programs that you are using and what export file are you creating.

[Fast Fox]

5 minutes ago, DWright said:

Can you please confirm which of the Affinity programs that you are using and what export file are you creating.

I am using Affinity Publisher. I am creating the document in CMYK/8 Fogra39 and exporting it to PDF/X1a.

[lacerto]

Obsolete.

[Fast Fox]

Thank you.

 I just converted to 16bit Grey scale from the Mode tab in Photoshop. It looks like this was Grey Gamma 1.8 and Dot Gain 20%. (I am using a PC)

The difference is similar to the above comparison which if you are right suggests that my image even though it looks a bit lighter is in fact likely to be OK?

[lacerto]

Obsolete.

[Fast Fox]

20 minutes ago, lacerto said:

It also depends on the kind of images that you have and whether there is "enough" contrast, and much of course on the kind of paper you are going to use. If it is strongly coated and glossy, there might be point in using Dot Gain 15, instead. Can you get any kind of a proof print?

Thanks,

 Yes I will be able to get some proofs from the paper. I will see how they come out and then look at the Dot Gain if I think it needs adjusting. I think your advice has helped me understand where the issue is if the proof does not come out quite right.