I'm creating a magazine in Indesign and have pdf ads that I imported and placed all throughout the magazine. The pdf ads are crisp and clear in their original format, but when I place them in Indesign, they're super blurry. I tried converting the pdf ads to a bunch of different formats (jpeg's, png's, etc), then placed them in Indesign. This reduces some of the blurriness, but when printed, they are still unreadable.
Do you have any idea why I'm having this problem, and how I might be able to fix it?