[sane-devel] Wrong colour scanning with HP 7400c

Erik P. Olsen erik at epo.dk
Sun Apr 23 11:02:13 UTC 2006

Rene Rebe wrote:
> On Sunday 23 April 2006 01:05, Erik P. Olsen wrote:
>> I am using FC5 with sane-backends 1.0.17 and each colour scan with my HP
>> 7400c has a yellow column of width 2-3 mm on the leftmost side of the
>> scanned image. I have scanned with an alternative piece of software and
>> here this yellow stripe is not present.
>> I assume it is a bug. What sort of documentation is needed to see what's
>> wrong?
> Aside the stripe the image is completely fine? Does it only happen when you 
> scan the whole page? E.g. is due to some plastic on the side and the other 
> software just allow scanning a smaller region? Or does it happen for scans
> in the middle of the page as well?

It does not happen with a smaller region. However, I can reduce the scan by so 
small an amount that the yellow stripe will still show up just smaller. But I 
can also see that the yellow stripe overlays the picture, so it is not some 
plastic on the side or similar, it is actually induced by the backend.

BTW, there is also a tiny green stripe about 1/5 of the width of the yellow stripe.
> What was the last version that worked?

I wish I knew. I mainly do gray scans which do not have this or similar effect. 
Just recently I had to do a lot of colour work and then noticed this yellow 
stripe effect. I can to a certain extent circumvent the effect by placing the 
source document approx. 1cm off the edge, do a preview scan, set the region 
accordingly and perform the scan. This is fine if I can use xsane but my 
application uses scanimage and then it becomes cumbersome.
> I'll try to find some time to pull the 7400 out of the shelft and give it a 
> try. But other work keeps me quite busy right now.

I am perfectly willing to perform any test you might wish, but perhaps it is 
faster if your can find time to connect your own 7400 :-)

Erik P. Olsen.

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