I've had to use a shotgun guess method.
1. Set the JPEG compression up ONE more percent. If 50% try 51%
2. Research the MOIRE PATTERN issue.
I am in the process of scanning my 1982 high school yearbook & want to upload them to a Facebook page to be viewed by former classmates. I have a Mac OS X 10.6.8 & have been scanning the book using a HP 6500 Officejet printer, which has a flatbed scanner. I have scanned in about 68 pages & about 20 of them have a waffle-look in the background of the page. It's not in the original & my scanner glass is clean. And when it comes through it doesn't always cover the whole page - some pages only show it in areas, both light & dark. The pages are scanning at 200 dpi automatically. I have played with the resolution settings & nothing changes. When I upload them the waffle-look is even more pronounced, to the point where you can't make out who's in some of the pictures, even in some of the larger pictures. There is no copyright issue & while one page has the waffle-look to it, the next page comes through sharp & clear. Yet both pages are clear in my original. I am baffled why this is happening & am wondering if someone has ever experienced this or knows what I can do. There are several copies of both earlier & later yearbooks on this Facebook page & nobody's experienced this type of problem. Thanks for any help you can offer.