So many artifacts. Don't scan in color when it's monochrome. Check the forum for some more hints on how to fix this. The fact that page 4 is so blotchy alone shows you've got a problem
@Zelinko That page was already like that in physical. http://images2.imagebam.com/82/4b/74/0a8544926178844.jpg I always scan monochrome pages in grayscale.