How to make black appear pure in exported PDF?

I have "Preserve pure black" selected and I fill the object with CMYK 0,0,0,100. This looks pure black on Corel Draw display, so far so good. But, when I export PDF, it appears as dark grey on the screen. How to achieve blacks appear as 0,0,0 for RGB and 0,0,0,100 for CMYK in an exported PDF?