Re: [hpoj-devel] ptal-hp scan changes (T series now supported!)

[Joe P. <joe...@sn...>]

On Sunday 06 May 2001 09:21 am, David Paschal wrote:
> Hi,
>
> I just checked in more changes for ptal-hp scan.  In particular, the
> OfficeJet T series is now supported.  In fact, between ptal-hp and SANE,
> there is now scanning support for every OfficeJet since (and including)
> the 500 series, and for every LaserJet MFP (except the 3100 and 3150).
>
> Other changes worth noting:
>
> - The default scan mode is now color for devices that support it, and gray
> otherwise.  (The 500 series now always outputs .pnm, not .jpg, as default.)
>
> - The default resolution is automatically changed to 300 when doing black
> and white scans on the OfficeJets (and also gray on the 500 series), to
> keep the device from hanging.
>
> - A checkin several days ago caused problems with scanning on pre-T-series
> OfficeJets.  That bug should be fixed now.
>
> - The JPEG improper length bug is still present for the OfficeJet 600, 700,
> and PSC 300.  However, I added a "-length" switch so one can override the
> default (too long) length of twice the width.  Keep in mind that on a
> scrollfed device, the length may vary between scans, even slightly for the
> same document.  I realize this isn't an optimal solution for this problem,
> but it's better than nothing while I look into a proper solution.
>

I'm happy to see color scanning begin to work.

Here are some of the results of the testing I did with the 600 using US 
letter-size (8.5x11) paper:

These combinations of -res and -length options (determined with the 
cursor-coordinate display in gimp) work fairly well with the 600.

-res 100 -length 1110
-res 150 -length 1680
-res 200 -length 2250

Some of the defaults work well. Using the command "ptal-hp mlc:par:0 scan 
-length 1110" produced a 100x100 color scan that didn't quite match the size 
of the original, but was close.

The scanned pages never seem to display or print at the original 
size (either too small or too large). For pc-assisted copying, would 
automatic scaling be needed?

The color scans always seem somewhat grainy, even at -res 200. My system 
doesn't handle color 300x300 scans well, so I haven't tried it again.

When trying to scan with "-res 200" , the printer often quits near the end of 
the scan and displays the LCD message "SYSTEM ERROR2252". I think it also 
happened once at -res 150. After power cycling the printer, it is able to 
scan again, but only after resetting  its clock. I used ptal-hp to do that.

When opening out.jpg in gimp, an error message often appears that is similar 
to  "Corrupt JPEG data: 8472 extraneous bytes before marker 0xd9". The number 
of extraneous bytes varies, but the message always ends in '0xd9'.

-- 
Joe