Tips for scanning manuals
I can deal with contributed scans in almost any format, so if you are used to scanning, please follow your own preferences and experience. If you aren't, or find it as easy doing it this way or that, consider the guidelines below.
Scanner settings
File format: even though I am going to make a PDF file out of the scans, scanning directly to PDF makes this more difficult. Rather use PNG or TIF, or if file size turns out to be a problem for storage or transfer, JPG can be used if the quality setting is not too low.
Resolution: 300 ppi is what I mostly use. If file size or scanning speed is a problem, 150 ppi is acceptable if all other settings are optimal (preferably not to be combined with JPG format). With 600 ppi more information is preserved, but I have to downsample it before putting the PDF on the web to make the file size acceptable for download.
Colour depth: Most scanning software allows you to choose between three modes: 24 bit (full colour), 8 bit (greyscale) and 1 bit (line art). The names might differ and there might be other modes as well, but these are the important ones. I prefer full colour on any page containing colour at all, and greyscale on the rest – even if the contents are just text or line art. Only for pages with line art containing very fine lines would it perhaps be better to use 600 ppi and 1 bit mode. However, to be successful this requires careful attention to the threshold level.
Labour saving techniques
When you have scanned page 1, keep scanning the rest of the odd-numbered pages without changing any scanner settings before starting on the even-numbered ones – there is no need to do a new preview scan for each page. If your software allows it, you can even turn on 180° rotation and continue with the even numbered pages without changing anything else.
The job becomes easier (and the strain on the spine of the book less) if you insead of using the scanner lid press the page to the scanner with your fingers or a moderately heavy book. The edges will perhaps look darker, but I always correct for this anyway.
You do not need to rescan a page if it turns out to be slightly rotated or off-center (as long as no content disappear) as this is easily corrected in software.
A final tip which unfortunately increases the amount of work somewhat is to place a sheet of black paper behind the page being scanned. This reduces the degree to which the text on the overleaf side shines through, and is thus most useful with books printed on thin paper. The effect is not only higher quality, but also smaller file size; a highly sought after combination.
File names
I have established a convention for naming the individual pages used both as file names and in order to refer to any page, even unnumbered ones. This system is detailed on a separate page.
Transfering the files
The files can be sent as email attachments, but only with a limited number of pages per message due to mail server limitations.
I can make a temporary user account to which files can be uploaded with scp (similar to FTP only more secure).
You can burn a CD and send it by mail.
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back | Tor Gjerde <i@old.no> |