Scanning in ubuntu
Issues related to scanning in (K)ubuntu.
Scanner: CanoScan LiDE 25
This was not recognized by Skanlite on Kubuntu 14.10 on my new pc.
Solution: Turn off xHCI in BIOS (under USB-settings). This might mean I no longer have USB 3 support, though :(
Sources:
Converting png to pdf
Skanlite doesn’t produce pdf-files, but it’s easy to convert from png or jpg to pdf with imagemagick:
convert input.png output.pdf
There are lots of options to convert:
-density 200x200Use 200 dpi-quality 60 -compress jpegCompress output with jpeg-compression with quality-setting of 60.
Shrinking large pdf files
If you have the original png-file from the scanning, shrinking this and converting it again is probably easiest, but if you only have the pdf, you can try using ghostscript to shrink it:
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf
You can increase the output quality by changing PDFSETTINGS to /ebook or /prepress (the default).
It should also be possible to shrink it with imagemagick,
by using convert input.pdf output.pdf with some settings of density, compression etc.,
but I’ve never got good results with this.
Sources: http://askubuntu.com/a/256449/13945
