PDF Export turns multiply effect into low opacity
Before I changed my preferences to view black accurately, the illustrator images I imported and set the effect to multiply displayed a solid black. After exporting to PDF, the black shows as faded and other layers' images are seeping through my black. I added an image to show this, if you look closely you can see the halftone dots are showing through the black parts of my image. I do not want this and only want the dots to appear in the negative space. How do I fix this? 
