[argyllcms] Re: basic icc profile for printer output using 24 patches?
- From: Gerhard Fuernkranz <nospam456@xxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 26 Jun 2007 01:54:52 +0200
Lars O. Grobe wrote:
>> A single device profile can be used to translate between PCS and
>> device values, so it is sometimes possible to print an equivalent
>> of something like the Macbeth Colorchecker if you know it's
>> XYZ or L*a*b* values, and use this as a verification mechanism
>> for a profile, if you have a D50 viewing environment in which
>> to do the visual check. This doesn't help you make the profile
>> in the first place though.
>
> I was hoping to be able to generate a profile compensating for the
> ink/paper and driver influence. I have 2x24 values: Those resulting from
> a scan of an original colorchecker, and those of the scan of the
> printout. The difference between these values should allow some kind of
> correction function to be applied. I know that I cannot get all
> parameters that are to be handled by a profile. I was wondering if there
> are routines to generate this matching table in the form of a simplified
> profile included in argyll.
>
> I have been using a similar approach for color correction with the tool
> macbethcal, which is part of the radiance light simulation distribution
> (radsite.lbl.gov). This also just created a simple correction function.
> The problem is that it works only on tiffs and not from inside
> applications, so I would have to establish an export-correct-print
> workflow for everything.
>
> Maybe I am completely wrong? Thank You for all the information... Lars.
You are not completely wrong, what you likely want is something like
this: http://argyllcms.com/doc/Scenarios.html#PP4
However, don't expect wonders. A scanner "sees" colors differently than
the human vision. This means, even if a scanner "sees" exactly the same
RGB values for a Colorchecker patch and an inkjet patch, these two
patches may still have a clearly distinguishable color for the human
vision (this effect may be stronger or weaker, depending on the
interaction between the used scanner, printer, printer driver, inks,
...). And only 24 patches (even if they were measured with a
spectrometer, and not with a scanner) do not really suffice for an
accurate printer characterization either. Another problem is that no
.cht file and no reference file for the 24-patch Colorchecker are
included in Argyll, so you'd need to make them yourself.
Regards,
Gerhard
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