#142 16bit doesn't work (CanoScan N670U)


I'm using gscan2pdf 0.9.31 on Crunchbang Linux with my Canon CanoScan N670U. In the scanning window, "Canon CanoScan N670U/N676U/LiDE20" appears on the top. I suppose this is the driver.

Everything works fine as long I scan in 8bit. Scanning in 16bit produces strange visual effects (see http://h9.abload.de/img/scan5blfa.png for a scan of a blank page with 16bit). Moreover, saving doesn't work if the image was scanned in 16bit. I get: "Error creating PDF image object: 16-bits of greylevel in png not supported. at /usr/share/perl5/PDF/API2/Resource/XObject/Image/PNG.pm line 119."

Either, my scanner doesn't support 16bit properly, in which case gscan2pdf shouldn't allow me to chose 16bit (it took me a while to find out why my scans where so grey…). Or, gscan2pdf has a problem with 16bit with that driver.

Please tell me which additional information you need. Thanks in adavance.


  • You are using a very old version of gscan2pdf and would suggest you try the latest version, just released, 1.0.5.

    Having said that, I doubt your particular problem has been fixed in 1.0.5.

    "Canon CanoScan N670U/N676U/LiDE20" is the scanner name that libsane reports.

    Please start gscan2pdf with

    gscan2pdf --debug (or better, if you upgrade to 1.0.5, gscan2pdf --log=log)

    and post the output from the command line (or the log file)

    The error message you are seeing is the fact that PDF::API2, the Perl module that gscan2pdf uses to write the PDFs, does not seem to support 16bit PNGs. However, almost certainly, 16bit scans would only be necessary for photos, and JPEG would be a better format than PNG.

    Therefore, please try saving a PDF with JPEG compression, rather than PNG.

    • status: open --> closed-out-of-date
    • Group: --> v1.0_(example)