[sane-devel] Making neutral scans

m. allan noah kitno455 at gmail.com
Fri May 21 18:17:10 UTC 2010

On Fri, May 21, 2010 at 1:53 PM, Grant <emailgrant at gmail.com> wrote:
>>>>>> Not at all. I've seen two different units of the same scanner give
>>>>>> very different tone scans with the same options set. You need a
>>>>>> reference target to scan.
>>>>>> allan
>>>>> But color management can be used after the fact, right?  I'd like to
>>>>> have a reference copy of everything I scan that I can apply things
>>>>> like color management or unsharp mask to later on.
>>>> Yes- if the colors are reasonable, a profile specific to that machine
>>>> could be used to clean it further
>>>> allan
>>> So if I make sure my gamma correction is always at 1.8 and I always
>>> leave all the sliders alone, I should be able to produce consistent
>>> reference scans that I can apply the same set of adjustments (ICC
>>> profile, maybe others) to later on to produce something as accurate as
>>> possible?
>>> I just want to make sure I'm not forgetting anything.
>> In theory, yes. But software upgrades might change a calibration algo,
>> and the sensors and lamp will drift over time, and the temperature in
>> the room will change, which might cause small changes. The only proper
>> way to get true stability is to run a color target periodically, and
>> rebuild your profile. That implies that you should be applying the
>> profile as you scan, or storing the scan of the color target serially
>> with your normal scans for later processing.
> Storing the scan of the color target as I scan is an interesting idea.
>  Could the same thing be done with a "white marks" target to later
> move pixels to eliminate artifacts?

Yes- though checking the manual for a calibration procedure would be easier :)

"The truth is an offense, but not a sin"

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