[Openicc] [argyllcms] Re: CC Profiles In X Specification and dispwin

[Hal V. Engel]

On Tuesday 15 January 2008 04:53:16 Kai-Uwe Behrmann wrote:
> Am 15.01.08, 07:10 -0500 schrieb Robert Krawitz:
> > That's correct -- I don't have the measurement hardware (nor do I
> > actually have every single printer, although I do have representative
> > samples of most of the newer Epsons).
>
> Once you can measure, the calibrations could greatly improve. If I
> understand correctly you do a basic calibration anyway. 

This calibration is currently done without the use of measurement devices.  I 
have done some linearization measurements of my printer/GutenPrint/CUPS setup 
using several spectrophotometers (DTP41B UV and a DTP20 UV).   For the most 
part the calibration state is good (actually considering that no measurement 
device was used surprisingly good) but I do see some places where there are 
issues in this area.  For my printer the most significant issue is an area in 
the magenta curve where there is a rather abrupt deflection in the curve near 
the mid point.   There is also a hump in the cyan curve at about its mid 
point.  Combined these cause a noticiable (but not large) green/cyan shift in 
the grays. 

It is when Robert and company are doing these base calibrations that the use 
of a measurement device would be most benifitial to them since it would allow 
them to detect issues like this and correct them.   This would result in a 
higher quality base configuration that would benifit everyone using the 
drivers even those who know nothing about color management.  It might also be 
possible to write some supporting software that would semi-automate the 
measurement/calibration workflow.  This is a non-trivial undertaking but it 
might be possible to eventually expose this functionality for users wishing 
to do custom calibrations of their own printing work flows.

> The next minor 
> step is to create a profile.

Possibily but no matter what you do one profile per printer is not going to 
work and creating a series of profiles for each printer is a large task.

> I'd like to add, as hardware I thought of a automatic xy chart table.
> Such device allowes to place the printed, dry chart on the table, tell
> about start and end points and continue with other things until the
> measurements are finished.

But getting the measurements is only a small part of the overall process.

>
> > That's also what I'd rather be doing.  In this particular case, I'd
> > rather add the necessary features to Gutenprint to allow people who do
> > have the hardware and expertise in this area to create and publish
> > these profiles, and for users to use them easily.

I agree that this is what you should be doing.  I also think that those of us 
with CM expertise need to be doing more to help you understand what needs to 
be done to achive this.

Hal