sane-canon(5)

NAME
sane-canon - SANE backend for Canon flatbed scanners

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

    CanoScan 300
    CanoScan 600
    CanoScan 2700F

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>.

DEVICE NAMES
This backend expects device names of the form:

    special

Where special is the path-name for the special device that corresponds to a SCSI scanner. The special device name must be a generic SCSI device or a symlink to such a device. The program sane-find-scanner helps to find out the correct device. Under Linux, such a device name could be /dev/sga or /dev/sge, for example. See sane-scsi(5) for details.

CONFIGURATION
The contents of the canon.conf file is a list of device names that correspond to Canon scanners. Empty lines and lines starting with a hash mark (#) are ignored. Only one device name can be listed in canon.conf.

TIPS

When scanning either slides or negatives, I found that I must set the gamma value to something about 2.2 to 2.4 (I set the same value for all three red, green, 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 after "Auto Focus", the image I get is often a bit too blurred. I found that using the GIMP to do a "Filter->Enhance->Sharpen" at about 40 to 60 improves the image quite a bit. In fact, I find it so good that I might implement a sharpen filter into the backend in the future.

The "native" scanner resolutions of the 2700F are the integer sub-multiples of 2720 dpi, i.e. 1360, 680, 340 and 170. You can scan at any other resolution, but you will notice that the image has noticeably more jaggies that when using one of the "native" resolutions.

FILES

@CONFIGDIR@/canon.conf
    The backend configuration file (see also description of SANE_CONFIG_DIR below).

@LIBDIR@/libsane-canon.a
    The static library implementing this backend.

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

ENVIRONMENT

SANE_CONFIG_DIR
    This environment variable specifies the list of directories that may contain the configuration file. Under UNIX, the directories are separated by a colon (`:'), under OS/2, they are separated by a semi-colon (`;'). If this variable is not set, the configuration file is searched in two default directories: first, the current working directory (".") and then in @CONFIGDIR@. If the value of the environment variable ends with the directory separator character, then the default directories are searched after the explicitly specified directories. For example, setting SANE_CONFIG_DIR to "/tmp/config:" would result in directories "tmp/config", ".", and "@CONFIGDIR@" being searched (in this order).

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(7), sane-scsi(5), sane-find-scanner(1)
http://www.rzg.mpg.de/~mpd/sane/
@DOCDIR@/canon/canon.install2700F.txt (installation of a CanoScan 2700F)

AUTHOR
Helmut Koeberle, Manuel Panea, and Markus Mertinat
Man page by Henning Meier-Geinitz (mostly based on canon.README)