[sane-devel] HP 4850C produces black images

[U.Mutlu]

Hi,
HP 4850C is supported by sane and is also recognised by scanimage -h.
Scanning using the usual apps (scanimage, xsane, LibreOffice) does work,
but the resulting image is all black (yes, there is a document to scan under 
the hood! :-).

How to fix this problem?

It is listed in /etc/sane.d/genesys.conf:
   # Hewlett Packard ScanJet 4850C
   usb 0x03f0 0x1b05
and, as said: all scan apps, incl. sane-find-scanner -v -v, do find it:

searching for USB scanners:
...
trying libusb:

<device descriptor of 0x03f0/0x1b05 at 003:008 (Hewlett-Packard HP Scanjet 
Scanner)>
...
<trying to find out which USB chip is used>
...
<This USB chip looks like a GL646_HP (result from sane-backends 1.0.24)>

found USB scanner (vendor=0x03f0 [Hewlett-Packard], product=0x1b05 [HP Scanjet 
Scanner], chip=GL646_HP) at libusb:003:008


(FYI: I've to start WinXP in VirtualBox and there LibreOffice to get scanning
with this scanner working. But I want to get rid of Windows; this is the
only remaining thing that isn't working for me yet under Linux).

OS: Debian 8 x86_64 w/stock kernel and the following *sane* related packages:

# dpkg -l | grep -i sane
ii  libsane:amd64             1.0.24-8
ii  libsane-common            1.0.24-8
ii  libsane-extras:amd64      1.0.22.3
ii  libsane-extras-common     1.0.22.3
ii  sane-utils                1.0.24-8
ii  xsane                     0.998-6+b1
ii  xsane-common              0.998-6

-- 
Thx