Everyone here is solving how to get paper into the Mac, which is the hard half. But there’s a second half nobody’s mentioned yet, and if you’re digitising 40 years of prints it’s going to bite you: what the files are called afterwards. A folder of Scan_0001.pdf through Scan_2000.pdf is technically a digital archive and practically a filing cabinet with the labels torn off.
I should disclose up front that I make a Mac app in this space, so I’m not a neutral party. I’m not here to sell you anything — the app isn’t the interesting part of this post. This is.
While building the part that decides which way up a scanned page goes, I measured something that surprised me and that I think matters for anyone scanning in bulk: Apple’s Vision text recognition reads upside-down text almost as happily as right-side-up text. Feed it a page rotated 180° and it returns roughly the same number of characters, at similar confidence. The characters are nonsense — “JE6Ed E |EIOI” where the page says “Total a pagar” — but if your software is deciding orientation by “which rotation produced the most text”, it’s deciding by coin flip. Mine was. That’s why some batches come out with a few pages mysteriously upside down.
What works instead is asking whether the recognised words are actual words. macOS has a spell checker built in and it’s multilingual, so you can score each of the four rotations by how many real dictionary words it produced. Right-side-up scores high, upside-down scores near zero, and the difference is unambiguous.
There’s a second trap underneath that one. My first version of this scored correctly on my test pages and still failed on a user’s real letters, because my test pages had headline-sized type and his had 11-point body text. The orientation check runs on a downscaled copy, and at that size body text is about ten pixels tall — unreadable, so every rotation scores zero and the software correctly gives up. Test with the smallest type you’ll actually scan, not the type that looks good in a screenshot.
The honest limit, also measured: on crumpled or handwritten paper the text reads about equally badly in every rotation, and no amount of cleverness fixes that. On those, the software should stop guessing and let you rotate it yourself.
If it’s useful to anyone: the app is Tidy, at tidymacapp.com, $9 once. But mostly I wanted to leave the orientation finding here, because it cost me two days and it applies to any scanning workflow, not just mine.