Yes, I believe NBC was looking closely for these things this whole time, and hadn’t found these phenomena on any of the ones he had looked at until now.
Actually, we had found them, the problem was either all of the halos were white on white (thus impossible to determine whether there actually was a halo) or might have come from the fact that the test scan was using a printout that already had halos.
NBC reply on his blog:
http://nativeborncitizen.wordpress.com/2013/08/19/to-4zoltanbutterdezillion/
To 4Zoltan/Butterdezillion
Posted on August 19, 2013 by NBC
4Zoltan: “What changes to the workflow cause halos, x-ray effect, and identical pixel elements? Why were they not showing up before and show up now?”
Was anyone looking for halos, x-ray effect, and identical pixel elements?
Are most PDFs given this type of scrutiny?
NBC: Halos, x-ray effects and identical pixels are found in all the PDF’s however, I am not satisfied with the amount of Halo I see in my WH scan.
BZ: Yes, I believe NBC was looking closely for these things this whole time, and hadn’t found these phenomena on any of the ones he had looked at until now.
NBC: That is not correct.
4Zoltan: Not sure if this is the x-ray effect.
If you load the PDF into Illustrator and release the clipping mask, one of the layers consists of the dark gray triangle in the center of the “A” in “USA” for the “USA TODAY” title. When you turn off that triangle in the center of the “A”, the underlying color is very close to the body color of the “A”.
NBC: That is an example, basically xray means that the background is not ‘white’ when you remove the foreground bitmap layers.