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Question

Scanned pics have a waffle-look to them :(

Aug 20, 2011 1:44PM PDT

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.
Melannie

Discussion is locked

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Answer
Since I can't see it.
Aug 22, 2011 5:27AM PDT

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.
Bob

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Re: Since I can't see it.
Aug 22, 2011 9:15AM PDT

I wish I could upload it here to show you. Sad

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When I need to share an image.
Aug 22, 2011 9:21AM PDT

I use photobucket.com
Bob

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Thanks!
Aug 22, 2011 10:17AM PDT

Thanks for the idea - never used photobucket! Never needed to! Shocked

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My first impression is that 72 DPI is not enough.
Aug 26, 2011 12:29PM PDT

You are seeing an effect that does have a name. It's something you see in silk screening and it has a name. But at 72 DPI and 24 bit color you may have to bump that to 100 to match your common LCD at least. I'd use 32 bit color too.
Bob

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Will try that...
Aug 27, 2011 9:14AM PDT

I did adjust my DPI setting both up & down but will try your suggestion. I ended up purchasing a VuPoint Magic Wand scanner & it worked great for this project. But I would still like to fix this for future reference/use. Thanks!! Happy