Following on from last week…
The other form of computer checking involves much more sophisticated software, and further reduces the chance of human error. In the process we’ve just been talking about, the letters were fed to me automatically, but I still had to use my brain to identify them and see that they were kosher. In this process, there’s barely any brain involved at all.
In this process, the operator uses a hand-held scanner to get the columns of text into the computer. Then it is run through OCR software – very clever software, which not only recognises letter glyphs but can also be taught to handle variations in glyphs caused by its being hand-written. Because it is a computer, it can also be taught some of the laws of whether a letter is kosher or not, so it can apply those mechanically to each glyph and flag up any doubtful cases.
Finally, the OCR output is compared to a Torah text, and any discrepancies are flagged up along with the doubtfully-kosher ones. A report with all problems is generated and given back with the scroll to the sofer, who then goes through the list and fixes everything on it.

Scan report
Scan report

Like this. Column 003, says the first entry on this report, which starts “Vayomer Adonai Elohim” – one comment. Line 21 (Bereshit 3:5), problem, thus: extra letter vav in the word “mimenu,” where it should say “…yodea Elohim ki b’yom akhalkhem mimenu v’nifkedu eineikhem…” and then in the picture you can see it’s got “v’mimenu,” for some reason or other.
I think I probably started writing the mem, got distracted mid-stroke, forgot I’d already started it, and started it over, but I don’t remember now.
Anyway.
Even this process, though, isn’t completely foolproof. Humans run the software, and as soon as humans come on the scene, there’s potential for human error.
If the various software operations aren’t applied properly – like forgetting to run the spellcheck on a document – the software won’t flag up problems because it won’t have looked for them. Perhaps the “is it there?” process on each letter of a column was run but the “is it kosher?” process accidentally wasn’t.
The computer needs human help to learn the writing, and perhaps the human isn’t paying attention. Perhaps the computer says “hey, human, what’s this?” and the human is half-asleep and says “vav” when he means “yud,” and a spelling mistake consequently goes unspotted.
Sometimes the software just can’t pick up on things. Very fine lines – the scanner might not pick them up; sometimes the presence or absence of a very fine line can be the difference between kosher and pasul. But we can’t (at present) scan to so high a resolution as to pick up on all these; the processing time would be prohibitive.
Finally, the letters are very slightly three-dimensional; a human, with stereo vision, can tell the difference between ink and shadow, and a scanner can’t always. Sometimes it’ll interpret a shadow as a crucial fine line, and report a letter kosher when it really isn’t.
So a scan is an excellent tool – I think it’s one of the finer syntheses of technological development and ancient ritual – but it does not replace all the other proofreading tools we use, and it is not a substitute for hard work and knowing your stuff. Few things are, really.