image processingpdfterminal
When I use imagemagick's convert jpeg to pdf tool:
convert *.jpeg output.pdf
an output PDF is created, but what I've noticed is that the even pages get rotated by 180°.
What's even stranger is that if I open the even pages with Preview, rotate them 90° right and then rotate them 90° left, and then save it and run the convert command again, the page doesn't get rotated 180°.
Is there anything I'm doing wrong over here?
This works for me on Mountain Lion:
Open all the JPG's in Preview so that the files are selectable within the one window, i.e. thumbnails of the JPG's are viewable in the selection pane located the window's left side.
Click in the selection pane and select all the thumbnails with Cmd-A.
Select File > Print... from the menu bar.
Select PDF > (from the drop down) Save as PDF... from within the Print Dialog.
Take it from there...
For the command-line I can recommend:
pdftk, the PDF Toolkit (for the Snow-Leopard installer you can try Pacifist to get the binaries or use the older version)
Merge PDF Documents
Split PDF Pages into a New Document
Rotate PDF Pages or Documents
…
If your PDF is edit-protected, you may want to try qpdf (via e.g. homebrew) to remove the restrictions first.
QPDF is a command-line program that does structural, content-preserving transformations on PDF files. It could have been called something like pdf-to-pdf. It also provides many useful capabilities to developers of PDF-producing software or for people who just want to look at the innards of a PDF file to learn more about how they work.
Best Answer
It seems like the scanner I used to scan the documents I was trying to make PDFs of was saving the images with an orientation property. These were the two properties:
Orientation: 1 (Normal)
Orientation: 3 (Rotated 180°)
So, although it looked as though the images were upright, every second image would technically be flipped 180°, which is the property that imagemagick would use.
Removing this property from multiple images should be possible on macOS using a tool like ExifTool.