Simon Browne

see also human reading, machine reading

Scanning is reading for particular details (such as names and numbers) by running one’s eyes over every word in a line. Sometimes I find myself using my index finger to guide my eyes when scanning a printed text. With a computer and full-text search capabilities, control-f helps find instances of a particular word or phrase.

Scanning is also a way to process printed matter so that it may be electronically archived, modified and distributed. A book scanner is the tool of choice for many archivists. It has two cameras, one to capture the odd pages, and one for the even pages. Most book scanners consist of a system of pulleys which allow the book to be raised to two perpendicular sheets of glass, laying the pages flat and ensuring the focus is correct. It’s quite a workout, and is usually reserved for books which are difficult to find in digital format. Essentially, the book scanner takes two photographs, one each for the even and odd sides of a spread. So the sequence goes: flip, click click, flip, click click, and so on, and so on. Next, these images must go through a variety of processes to produce a digital book: rotating, cropping to the size of the page, merging into a single PDF. Ultimately, the most useful digital books include a digital text layer generated by OCR (Optical Character Recognition) software, making the text searchable and copy/pasteable.

Image: An archivist book scanner