Rotations Rotations…

Hermitian may have missed where I explained how, by scanning the image upside-down, the final PDF shows the images rotated in the same direction as the WH LFBC PDF. This makes a lot of sense, IF you understand how the images are captured by the scanner, and why they are in landscape orientation in the first place. Note that a rotate operation in Preview does not rotate the internal images but rather changes the cm matrixes. Which makes a lot of sense of course when you realize that rotating a JPEG is non-trivial until you have decompressed it again into its raster format… This is not rocket science but does require a bit of thought.

The scan is rotated clock-wise but I bet I can change that depending on the orientation of the input. Needless to say, we see all the identifying markers. Incomplete separation of the information into the background and foreground, multiple foreground layers. It’s not perfect but it’s good enough to be able to reject most of the Cold Case Posse’s findings.


The images are also rotated 90 degrees clockwise, unlike the WH PDF which led me to the prediction that the staffer scanned the document upside down and used Preview to correct this.


The next step is to compare the rendering instructions in the WH LFBC PDF and the Xerox 7355 PDF saved with preview. Finally I show how an upside down scanned document after being rotated in Preview matches the WH LFBC.

Note how the Upside Down rotated image matches the WH LFBC. Which is why I have concluded that the reason preview was used was to rotate an upside down scan.



2 thoughts on “Rotations Rotations…

  1. What are the rotation values for these VP Biden’s tax returns after being saved in Preview?
    (BTW, this is not the 2009 taxes but the 2008 1040)$file/J_Biden_2010.pdf

    Both made with the 7655. Both load in landscape in Illustrator but facing different directions.

    I would assume that their rotations values are different either in value (90 degrees versus 180 degrees) or in sign (both 90 degrees but one positive, the other negative).

    I would do it but let my Mac at home and won’t have access for several days.

Comments are closed.