Can CMYK switch to RBG in the printing process?

[Madeline]

Every one of my illustrations was set up as CMYK.  Yet the printing company told me that because my transparent objects may be in the RGB mode, they are causing problems regarding correct color printing by converting the page to the RGB mode.

 

I have my doubts about this because the first proof was printed as a perfect match to the original colors of my AD illustrations.  Also, some of the pages that have incorrect color do not contain any gradients or use of transparent images.

 

Please tell me if there is a way to see if any of my images are in fact in RGB mode despite my setting each page up as CMYK.  I'm trying to get to the bottom of this and have such limited knowledge. This is my first experience with Affinity Designer and self-publishing

 

They also suggested I flatten my file before saving as a PDF.  I can't begin to figure out how to do this.  I had exported the entire document with the preset PDF (flatten).  Is that correct?  

 

Please help me with these issues.

 

Thank you!

[MikeW]

Upload the pdf in queston and I'll check it out or you can use Acrobat to do so. It would be good also to see the pdf that generated the good proof.

 

But if they want rgb then I suspect that is the color model you should be using and you should also know what pdf profile they use.

 

Mike

[Madeline]

Thanks, Mike.  They want CMYK which is what I set up in AD.  They are saying that the transparent objects are causing a shift to RGB during the printing process which is causing the color problems.   I would be happy to upload the PDFs. I could choose some individual pages rather than the whole book.  How can I send it to you?

[MikeW]

Hi Madeline,

 

I think it would be best to see exactly what they got. You could zip the pdfs and upload to dropbox and then send me a private message for the download link. I'll look at them straight away once it gets downloaded.

 

Mike