sane-canon(5)

NAME
sane-canon - SANE backend for Canon SCSI scanners

DESCRIPTION
The sane-canon library implements a SANE (Scanner Access Now Easy) backend that provides access to the following Canon flatbed and film scanners:

    CanoScan 300
    CanoScan 600
    CanoScan FB620S
    CanoScan FS2700F
    CanoScan FS2710

No parallel port and USB scanners are supported and there are no plans to support them in the future.

IMPORTANT: this is alpha code. Don't expect this to work correctly. Many functions are missing, others contain errors. In some cases, your computer might even hang. It cannot be excluded (although I consider it extremely unprobable) that your scanner will be damaged.

That said, TESTERS ARE WELCOME. Send your bug reports and comments to Manuel Panea <mpd@rzg.mpg.de>; for questions concerning the FB620 contact Mitsuru Okaniwa <m-okaniwa@bea.hi-ho.ne.jp>, for the FS2710 Ulrich Deiters <ukd@xenon.pc.uni-koeln.de>.

TIPS (FS2700)

Scanning either slides or negatives has been found to require rather large gamma corrections of about 2.2 to 2.4 (same value for red, green, and blue). Also, for slides, using "Auto Exposure" helps a lot.

The "Auto Exposure" function for slides makes the scanner do a first pass on the film to determine the Highlight and Shadow point values. The "Auto Focus" function triggers yet another pass to determine the focus value. After that, the real scanning pass takes place. The "Auto Exposure" function is not available for negatives yet.

Even with "Auto Focus" turned on, the scanned image is often a bit too blurred. Using the GIMP to do a "Filter->Enhance->Sharpen" at about 40 to 60 improves the image considerably. It is likely that a sharpen filter will be included in a future version of this backend.

The "native" scanner resolutions of the 2700F are the integer sub-multiples of 2720 dpi, i.e. 1360, 680, 340 and 170. Scanning at other resolutions is possible, but there will be noticeably more jaggies in the image than when using one of the "native" resolutions.

TIPS (FS2710)

Gamma corrections are done not by the scanner, but by the backend. The scanner is always run in 12-bit mode. In "color" mode the image data are corrected for gamma, shadow point, etc., and then truncated to 8-bit intensities; the default gamma value is 2.5. In "raw" mode the image data are exported without corrections as 16-bit intensities; this mode can be recommended if extensive adjustments have to be made to a picture (and if the frontend can handle 16-bit intensities).

Negatives are handled by simple color inversion and may require manual removal of blue discoloration.

FILES

/usr/lib/sane/libsane-canon.a
    The static library implementing this backend.

/usr/lib/sane/libsane-canon.so
    The shared library implementing this backend (present on systems that support dynamic loading).

ENVIRONMENT

SANE_DEBUG_CANON
    If the library was compiled with debug support enabled, this environment variable controls the debug level for this backend. Higher debug levels increase the verbosity of the output. Example: export SANE_DEBUG_CANON=4

SEE ALSO
sane-scsi(5)
http://www.rzg.mpg.de/~mpd/sane/
doc/canon.install2700F.txt (installation of a CanoScan 2700F

AUTHOR
Helmut Koeberle, Manuel Panea, and Markus Mertinat; FB620S support by Mitsuru Okaniwa; FS2710 support by Ulrich Deiters
Man page by Henning Meier-Geinitz (mostly based on canon.README)