Here is a detailed report by someone who purports to be a PDF expert, who consulted to the Maricopa County Sheriff's Department's team on this. I know enough about this subject to know that I don't know enough to tell whether she is right, wrong, or overly sure of herself.
I mentioned last year that one of my students was showing me Obama's birth certificate and all the layers when you open it in Illustrator--and I saw something that she missed: different parts of the birth certificate appear to have been scanned at different resolutions:
Diagonal lines, when scanned, produce a jagged set of pixels. This is an artifact of how sharply drawn the line is, and the scan resolution (dots per inch). All things being equal, two lines drawn at the same angle should produce similar levels of jagged pixels. Yet when I looked at the mother's maiden name, "Dunham" at 800% in Adobe Acrobat, I noticed that the diagonals on the "D" are very, very noticeably different in their pixelation than the diagonal lines of the letters in the rest of the name.As I said last year, this alone does not prove fraud, but it is most curious.
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The attendant's name (the doctor who delivered the child with the halo over his head) has the same jagged, low-resolution characteristics as the "D" in Dunham--but not the "unham." (This was 600%.)
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Now, it doesn't really matter if the birth certificate is a fraud. Once the mainstream media have decided that an idea is nonsense, you have to give up, and work on persuading Americans that they should not re-elect a guy who has destroyed a bad economy. But I am curious to know if this report is correct or not, mostly out of intellectual curiosity.