Alexandre Abbes wrote: > Hi I have a snapscan 310, which has an optical resolution at 300dpi. > Thus the xsane button only proposes resolution up to 300dpi. But I > know that with a good interpolation, one can scan with this scanner > up to 1200dpi. Does anybody know how interpolation works? Is it a job > done by the scanner itself, or a soft post-prossessing that can be > done with gimp? Any comment welcome ! Alex
As far as I know, you can never get more than the optical resolution (unless you do weird tricks like moving the scanner head sideways in sub-pixel steps or something). Creating a 1200 dpi from a 300 dpi scan is just fooling yourself. It's like converting an mp3 from 64 kB/s to 256 kB/s, it takes more hd space but the quality stays the same (or even gets a little worse). One case that I can imagine is that the scanners' CCD has a resolution of 300 dpi (=horizontal resolution), but can do motor steps with a higher resolution (=vertical resolution = e.g. 1200 dpi).(=vertical). In that case I can imagine that it makes sense to interpolate to 300x1200 dpi. I think that usually interpolation is done in software, to keep the amount of data that the scanner has to send as small as possible. Bertrik
