Document background fades when exported to PDF

[Ebba265765757fed]

I've created an InDesign document with a dark blue background (check linked photos), set to CMYK. When I try to export the document to PDF (note: i have tried every possible setting) the background colour fades, as if it was set to RGB - even though I have made sure to set everything as CMYK. I have tried to export it with press quality, highest quality, different versions and you name it - and nothing seems to work. 

How can I fix this? 

Thanks,

Ebba

[Eugene Tyson]

What's the colour breakdown in InDesign?
What's the colour breakdown in the PDF?

InDesign preview is not 100% reliable

Viewing a CMYK pdf in Acrobat is not reliable as you're viewing on a RGB device.

The CMYK values is what matters here, I would say.

[Bill Silbert]

Are you viewing the PDF in Acrobat or are you using some other PDF viewer? If you are using a different viewer then try Acrobat. 

[Peter Spier]

Make sure the traansparency blend space and your swatch colors are all in the same color model.