# Re: Patch for Microtek ScanMaker X6 (microtek2 backend)

Bernd Schroeder (bernd@aquila.muc.de)
Sat, 21 Nov 1998 17:54:19 +0100

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Hi,

On Thu, Nov 19, 1998 at 11:57:34PM -0500, Christian Grigis wrote:
>
> Hello,
>
> On Fri, 20 Nov 1998, Bernd Schroeder wrote:
>
> > On Thu, Nov 19, 1998 at 03:53:49PM +0100, Sebastian Erdmann wrote:
> > >
> > > my Microtek Scanmaker X6 exhibits some strange behavior: After
> > > switching it on, colors (or greyscale tones) are "washed out" and
> > > horizontally unbalanced across the image. This occurs when using
> > > SANE 0.74 as well as SANE pre1.00. A simple workaround is to
> > > power-cycle the scanner (while keeping the computer running).
> >
> > This sounds indeed strange. Normally the scanner should be in reset state
> > after it is switched on. Or are the colors wrong if the scanner is switched
> > on before the system is booted (or the SCSI driver is loaded) ? Then
> > the SCSI driver sends one or more commands to the device, but these
> > commands should not affect the results of a scan.
>
> I just acquired a ScanMaker X6EL, and I noticed the same strange
> behavior: the scanned image is OK after a powercycle, but the following
> scans result in "weird" colors.
> I have not had time to investigate the problem so far, but here is
> some additional info:

I think it is not the same problem, it is more or less the other way
round.

Can you try the following: when the colors are wrong, do a lineart scan,
and then again a color scan. It would be interesting to know, whether
the colors are correct again (at least for one scan). Some models
show this behaviour, and the current workaround is to set up the parameters
for a B/W scan before every scan and scan one line (or zero lines
in the next release). This is, what do_dummy_scan() does
(see the discussion in the other thread).

> The problem seems to happen for 24-bit Color and 8-bit Gray modes.
> 36-bit Color and 12-bit Gray never result in a correct image (is that
> because Gimp does not interpret those color schemes correctly?), and
> LineArt is always correct.
> By the way, 36-bit Color and 12-bit Gray modes seem to be handled
> differently by scanimage and xscanimage: xscanimage does not complain, but
> scanimage gives the following messages, apparently not understanding those
> modes:

At present I do not know what scanimage does, but it appears, that it
indeed doesn't handle more than 8 bits per color. xscanimage has #ifdef's
in the code. I think, that these #ifdef's mean, that it refuses to scan
with more than 8 bits, if it is running as a plugin for the gimp, otherwise
it scans. But apparently it doesn't store this information correctly in
the image file.

If you do a 12-bit grayscale scan, and change the fourth (?)
line in the resulting pnm file from 255 to 65535, the image should be
correctly displayed with xv. xv again reduces the color depth to 8 bits,
but at least it seems to understand more than 8 bits. To my knowledge
there are not many applications, that can handle more than 8 bits per color.

> Finally, here is a mini-patch to have the scanner attributes
> display correctly the X6EL model name:
>
> --- microtek2.c.back Thu Nov 19 22:36:26 1998
> +++ microtek2.c Thu Nov 19 22:05:53 1998
> @@ -2235,6 +2235,7 @@
> case 0x92: fprintf(stderr, "E3+ or Vobis Highscan"); break;
> case 0x93: fprintf(stderr, "ScanMaker 330"); break;
> case 0x97: fprintf(stderr, "ScanMaker 636"); break;
> + case 0x98: fprintf(stderr, "ScanMaker X6EL"); break;
> default: fprintf(stderr, "Unknown"); break;
> }
> fprintf(stderr, ")\n");

Thanks,
Bernd

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    Bernd Schroeder
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