how to calibrate scanner for scanimage

English Hardware
#1

Hi,

can anyone give me a hint how I could calibrate my scanner for color scans with scanimage?

Would Ihave to get a calibration test sheet?

thanx
paul

#2

This is in the hardware forum. Any chanve you tell which hardware this is about?

#3

If the functionality is not built into your scanner, you will need to use imaging software to adjust the images after the scan. If it is, it should show up in your scanner’s control panel.

#4

it’s a canon canoscan 9000f
I thought it is a basic problem - relevant for all scanners.

#5

my question relates to scanimage, which is a command line tool having no such thing as a control panel. (or did I misunderstand your answer?).
If I have to adjust the images after the scan, how would I do that in an automated way? by which SW and how would I establish correction tables?

#6

I don’t know if what you want is possible. Point is that I don’t see any callibration options, neither in scanimage --help, nor in the GUI’s. If the scanner does not provide correct colors, a worn out lamp could be the problem. Which AFAIK can only be corrected by replacing the tubelamp. Which -again AFAIK- is far more expensive than a new all-in-one.

#7

On 2013-02-22 15:16, Knurpht wrote:
>
> I don’t know if what you want is possible. Point is that I don’t see any
> callibration options, neither in scanimage --help, nor in the GUI’s. If
> the scanner does not provide correct colors, a worn out lamp could be
> the problem. Which AFAIK can only be corrected by replacing the
> tubelamp. Which -again AFAIK- is far more expensive than a new
> all-in-one.

Many (all?) scanners have a built in test pattern, hidden behind the top
of the glass. When the scanner inits, the head moves up and down,
finding the top of the scan area, and goes a bit behind it to scan that
test area, which is used for automatic calibration of the unit. The lamp
is expected to degrade, after all.

It is possible that years ago this was done manually, but I have never
seen it nor know how it could be done.

–
Cheers / Saludos,

Carlos E. R.
(from 12.1 x86_64 “Asparagus” at Telcontar)

#8

you are right. modifying the scan via scanimage directly is probably only possible via the option --gamma-table that affects all colors equally.
maybe I had a wrong setting there.
I thougt color correction should be possible since xsane has an option color management that allows to load files with ICM color profiles. of course I don’t know whether that option is active for my scanner.

it should however be possible to calibrate the scanned images for the monitor and/or the printer. the web mentions IT-8 test targets for that purpose.
this, however, might be a topic for the applications sub-forum.
I’d be grateful a any hint in that direction.

I have the idea that color calibration should somehow be possible eg. with gimp.

#9

I don’t have any experience of Canon scanners but HP scanners do have a GUI control panel which allows a wide range of settings to be adjusted. I have a very simple scanner which I would not expect to offer colour management but, if it is available, I would expect it to be set using some sort of GUI control panel as a superior version of the test panel to which Carlos refers.