Printers with full Color Management

[david-vj]

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[Milan Knížek]

davidvincentjones píše v Čt 27. 08. 2009 v 16:28 -0700:
> Has anybody found a printer series that provide full Color Management with
> DigiKam under Linux? I am looking for a replacement unit that prints up to
> 13" wide.

The question is confusing - if you have a supported printer (i.e. driver
for linux) and a printer profile, then the printer can be colour
managed. This is not dependent on digiKam.

Have a look at linuxprinting.org for a list of well supported printers.
I use Epson P2100 (quite old today).

Printing in linux usually uses CUPS (spooler), which takes care about
conversion of the data for the printer drivers (gutenprint for Epson).
Some apps (GIMP, CinePaint, PhotoPrint) convert data directly to
gutenprint, even that they use CUPS for spooling.

As far as I know, neither CUPS or the drivers are capable of recognising
the embedded colour space (image profile) and converting to printer's
colour space (profile). Hence this work must be done by the application
- either manually before printing or on-the-fly during printing.

In digiKam: the print dialog in current beta offers to convert to
printer's profile on-the-fly, but I have not tested this part yet.

NB the profiles, which were prepared for MS Windows or Mac OS, are of no
use in linux.

regards,

Milan Knizek
knizek (dot) confy (at) volny (dot) cz
http://www.milan-knizek.net - About linux and photography (Czech
language only)

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Op vrijdag 28 augustus 2009, schreef Milan Knížek:

  > NB the profiles, which were prepared for MS Windows or Mac OS, are of no
  > use in linux.

Is this true?

Caspar.
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[Geert Janssens]

On Friday 28 August 2009, Caspar Maessen wrote:
> Op vrijdag 28 augustus 2009, schreef Milan Knížek:
>   > NB the profiles, which were prepared for MS Windows or Mac OS, are of
>   > no use in linux.
>
> Is this true?
>
This seems odd to me as well. Can you give more details about this ?

Geert
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[david-vj]

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[Markus Spring]

For printing with color management under linux you might like to have a look at

http://jcornuz.wordpress.com/2007/12/06/printing-3-printer-color-management/

and for an overview see all his entries on color management in

http://jcornuz.wordpress.com/table-of-contents/

Joel does not use kde, so he is not in the digikam boat, but his articles on
color management and calibration in linux are among the best i have found

Markus
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[Marcel Wiesweg]

>
> I am using the HPLIP/CUPS driver that has no adjustment for the various
> papers and trying to get the screen image to correctly be represented on
> paper is a very hit and miss experience. The Color Management > Soft Proof
> configuration in digiKam (at least using Windows ICCs) does not appear to
>  be having any effect .. at least with my printer.

Please note that color management has had quite a few bugs. 1.0-beta4 will fix
most of those, except for the soft-proof plugin, which needs some more care
still. You can specify a color profile in some print dialog, that should work,
though untested (no color printer here)

Marcel
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[Milan Knížek]

Geert Janssens píše v So 29. 08. 2009 v 10:47 +0200:
> On Friday 28 August 2009, Caspar Maessen wrote:
> > Op vrijdag 28 augustus 2009, schreef Milan Knížek:
> >   > NB the profiles, which were prepared for MS Windows or Mac OS, are of
> >   > no use in linux.
> >
> > Is this true?
> >
> This seems odd to me as well. Can you give more details about this ?

The only chance for using the profiles prepared for the vendor's driver
for MS Windows would be, if the vendor created a driver also for linux
(with the same behaviour) or if the existing linux driver imitated the
original MS Windows driver pretty well.

I use EPSON printer and EPSON does not provide linux drivers. Gutenprint
is told to be actually better than the original MS Windows driver (which
of course means, that it behaves differently).

Have a look also here:
http://jcornuz.wordpress.com/2007/12/06/printing-3-printer-color-management/

In other words, when you find an ICC profile on the internet, you also
need to know the circumstances, which existed for its preparation. E.g.
camera icc profile prepared for Adobe Lightroom will most probably
provide different colours in UFRaw. Not saying worse or better, but
different. But yet - if you do not have anything better and are happy
with the result, do not worry.

The only lucky exception are the display icc profiles. You can use tools
to calibrate the display in MS Windows and then use this icc profile in
linux. The reason is that it seems that the display driver works the
same. If your calibration tool is supported by argyllcms, you can check
yourself (this great pack of cms tools work on linux and MS Windows,
too).

hope this helps.

regards

Milan Knizek
knizek (dot) confy (at) volny (dot) cz
http://www.milan-knizek.net - About linux and photography (Czech
language only)

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[Geert Janssens]

On Tuesday 1 September 2009, Milan Knížek wrote:

> Geert Janssens píše v So 29. 08. 2009 v 10:47 +0200:
> > On Friday 28 August 2009, Caspar Maessen wrote:
> > > Op vrijdag 28 augustus 2009, schreef Milan Knížek:
> > >   > NB the profiles, which were prepared for MS Windows or Mac OS, are
> > >   > of no use in linux.
> > >
> > > Is this true?
> >
> > This seems odd to me as well. Can you give more details about this ?
>
> The only chance for using the profiles prepared for the vendor's driver
> for MS Windows would be, if the vendor created a driver also for linux
> (with the same behaviour) or if the existing linux driver imitated the
> original MS Windows driver pretty well.
>
> I use EPSON printer and EPSON does not provide linux drivers. Gutenprint
> is told to be actually better than the original MS Windows driver (which
> of course means, that it behaves differently).
>
> Have a look also here:
> http://jcornuz.wordpress.com/2007/12/06/printing-3-printer-color-management
>/
>
> In other words, when you find an ICC profile on the internet, you also
> need to know the circumstances, which existed for its preparation. E.g.
> camera icc profile prepared for Adobe Lightroom will most probably
> provide different colours in UFRaw. Not saying worse or better, but
> different. But yet - if you do not have anything better and are happy
> with the result, do not worry.
>
> The only lucky exception are the display icc profiles. You can use tools
> to calibrate the display in MS Windows and then use this icc profile in
> linux. The reason is that it seems that the display driver works the
> same. If your calibration tool is supported by argyllcms, you can check
> yourself (this great pack of cms tools work on linux and MS Windows,
> too).
>
> hope this helps.
>

Doh, I used to know this.

Yes you are absolutely right, the piece of software interfacing the hardware
is as critical to the output as the hardware itself. Change the software (for
example, change from Windows to Linux) and you most likely have to recreate
ICC profiles. Just liky you have to recreate ICC profiles if you change your
physical printer.

Thanks for making me remember...

Geert
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[Marcel Wiesweg]

> camera icc profile prepared for Adobe Lightroom will most probably
> provide different colours in UFRaw. Not saying worse or better, but
> different. But yet - if you do not have anything better and are happy
> with the result, do not worry.

The part about the printer is clear to me, but where is the difference for RAW
files? I see there can be differences in RAW development - demosaicing
algorithms etc. - but once you have your colors in uncalibrated color space,
applying the color conversion using the input color profile should be the
same?

Marcel
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[Milan Knížek]

Marcel Wiesweg píše v Út 01. 09. 2009 v 19:49 +0200:

> > camera icc profile prepared for Adobe Lightroom will most probably
> > provide different colours in UFRaw. Not saying worse or better, but
> > different. But yet - if you do not have anything better and are happy
> > with the result, do not worry.
>
> The part about the printer is clear to me, but where is the difference for RAW
> files? I see there can be differences in RAW development - demosaicing
> algorithms etc. - but once you have your colors in uncalibrated color space,
> applying the color conversion using the input color profile should be the
> same?

I cannot provide much technical details at this area, just a laic
understanding of the information available on ufraw and argyllcms
mailing lists...

AFAIK, the thing is that not all converters apply the same steps in the
same order and that some of the steps are variables affecting the raw
and rgb data. Some of the settings can be set by the user, some may be
hidden (and proprietary).

E.g. UFRaw applies white balance, highlight-reconstruction, wavelet
de-noising, raw curve adjustment, gamma and linearity before assignment
of the camera profile.

Next problem is that the camera sensor does not react fully linearly to
the light - hence an icc profile prepared for a particular
white-balance/raw curve/etc. and used for another
white-balance/curve/etc may provide different result even in the same
raw converter.

If my understanding is wrong, I would be more then happy to know other
opinions.

P.S.2 The difference is quite obvious when using Canon's Digital Photo
Professional and UFRaw. There are methods how to find out, which ICC
profiles are used by DPP in MS Windows. However, people were usually not
able to get the same output from UFRaw with those profiles. (I tried
myself and skipped this approach - the Adobe Matrices in dcraw based
converters provide better results).

regards,

Milan Knizek
knizek (dot) confy (at) volny (dot) cz
http://www.milan-knizek.net - About linux and photography (Czech
language only)

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[Gerhard Kulzer]

On Friday 04 September 2009 09:47:24 pm Milan Knížek wrote:

> Marcel Wiesweg píše v Út 01. 09. 2009 v 19:49 +0200:
> > > camera icc profile prepared for Adobe Lightroom will most probably
> > > provide different colours in UFRaw. Not saying worse or better, but
> > > different. But yet - if you do not have anything better and are happy
> > > with the result, do not worry.
> >
> > The part about the printer is clear to me, but where is the difference
> > for RAW files? I see there can be differences in RAW development -
> > demosaicing algorithms etc. - but once you have your colors in
> > uncalibrated color space, applying the color conversion using the input
> > color profile should be the same?
>
> I cannot provide much technical details at this area, just a laic
> understanding of the information available on ufraw and argyllcms
> mailing lists...
>
> AFAIK, the thing is that not all converters apply the same steps in the
> same order and that some of the steps are variables affecting the raw
> and rgb data. Some of the settings can be set by the user, some may be
> hidden (and proprietary).
>
> E.g. UFRaw applies white balance, highlight-reconstruction, wavelet
> de-noising, raw curve adjustment, gamma and linearity before

assignment

> of the camera profile.
>
> Next problem is that the camera sensor does not react fully linearly to
> the light - hence an icc profile prepared for a particular
> white-balance/raw curve/etc. and used for another
> white-balance/curve/etc may provide different result even in the same
> raw converter.
>
> If my understanding is wrong, I would be more then happy to know other
> opinions.
>
> P.S.2 The difference is quite obvious when using Canon's Digital Photo
> Professional and UFRaw. There are methods how to find out, which ICC
> profiles are used by DPP in MS Windows. However, people were usually

not
> able to get the same output from UFRaw with those profiles. (I tried
> myself and skipped this approach - the Adobe Matrices in dcraw based
> converters provide better results).
At least theoretically you are wrong in the sense that color management
should be independent of MS or Linux or whatever, it's the very sense of it.
CM transforms an image from one color space into another by transiting
through an ideal color space, it's a mathematical operation not dependent
on any drivers.
But then there is the question as to whether the CM has been correctly
implemented by a specific program or driver.  

I've been trying to find out what profile Canon is using in DPP for my 30D,
then 40D and 50D. For the 30D I could track that DPP loaded a certain
profile, but for the 40D and 50D DPP doesn't seem to load any profile, it's
built-in. I've tried all profiles delivered with DPP on Linux with UFRaw and
digiKam - none of them gives the same results than DPP, unfortunately. I
believe Canon is playing games with us, they use their own "kitchen" and
don't give it away. I believe (and I haven't pursued that allay yet) the two
only ways to get a profile for the latest Canons are
1. doing your own profile,
2. Look into what Adobe is doing in their Raw converters.

Gerhard

> regards,
>
> Milan Knizek
> knizek (dot) confy (at) volny (dot) cz
> http://www.milan-knizek.net - About linux and photography (Czech
> language only)
>
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> https://mail.kde.org/mailman/listinfo/digikam-users
>

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[Milan Knížek]

Gerhard Kulzer píše v Ne 27. 09. 2009 v 08:55 +0200:

> On Friday 04 September 2009 09:47:24 pm Milan Knížek wrote:
> >
> > AFAIK, the thing is that not all converters apply the same steps in the
> > same order and that some of the steps are variables affecting the raw
> > and rgb data. Some of the settings can be set by the user, some may be
> > hidden (and proprietary).
> >
> > E.g. UFRaw applies white balance, highlight-reconstruction, wavelet
> > de-noising, raw curve adjustment, gamma and linearity before
> assignment
> > of the camera profile.
> >
> > Next problem is that the camera sensor does not react fully linearly to
> > the light - hence an icc profile prepared for a particular
> > white-balance/raw curve/etc. and used for another
> > white-balance/curve/etc may provide different result even in the same
> > raw converter.
> >
> > If my understanding is wrong, I would be more then happy to know other
> > opinions.
> >
> > P.S.2 The difference is quite obvious when using Canon's Digital Photo
> > Professional and UFRaw. There are methods how to find out, which ICC
> > profiles are used by DPP in MS Windows. However, people were usually
> not
> > able to get the same output from UFRaw with those profiles. (I tried
> > myself and skipped this approach - the Adobe Matrices in dcraw based
> > converters provide better results).
> At least theoretically you are wrong in the sense that color management
> should be independent of MS or Linux or whatever, it's the very sense of it.
> CM transforms an image from one color space into another by transiting
> through an ideal color space, it's a mathematical operation not dependent
> on any drivers.
> But then there is the question as to whether the CM has been correctly
> implemented by a specific program or driver.  

That is misunderstanding of the previous discussion - while we can
assume the differences between CM engines are reasonably small, the
first problem of impossibility to use DPP's ICC profiles for UFRaw lays
with the fact that different image data are fed to the CM engine. I.e. I
also agree with your statement (on the theoretical level).

In another words, if UFRaw was able to "develop" the same image data as
DPP does (i.e. demosaic, denoise, curve, white-balance, whatever
else...), then we could use DPP's ICC profiles in UFRaw, too.

> I've been trying to find out what profile Canon is using in DPP for my 30D,
> then 40D and 50D. For the 30D I could track that DPP loaded a certain
> profile, but for the 40D and 50D DPP doesn't seem to load any profile, it's
> built-in. I've tried all profiles delivered with DPP on Linux with UFRaw and
> digiKam - none of them gives the same results than DPP, unfortunately. I
> believe Canon is playing games with us, they use their own "kitchen" and
> don't give it away.
My understanding is that DPP (as any other RAW converter) is using CM
techniques just as part of the RAW conversion process. As long as we do
not know what they do (before or after CM transforms), the profiles are
difficult to use elsewhere. As you wrote, it is possible that some RAW
converters skip the standardised CM transform in full and do things
their own way completely...

The issue similarly applies to printing: the CM standards do not
describe all of the variables of the RGB printing process (dithering,
mixing light/dark inks, substitution of RGB data with CMYK, ...), which
affect colour appearance of the printout, hence it is the work of the
driver (known as the printing RIP). As long as the drivers do different
things, the ICC profiles cannot be mixed among the drivers.

Regards,

Milan Knizek
knizek (dot) confy (at) volny (dot) cz
http://www.milan-knizek.net - About linux and photography (Czech
language only)

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[Gilles Caulier-4]

2009/10/4 Milan Knížek <[hidden email]>:

> Gerhard Kulzer píše v Ne 27. 09. 2009 v 08:55 +0200:
>> On Friday 04 September 2009 09:47:24 pm Milan Knížek wrote:
>> >
>> > AFAIK, the thing is that not all converters apply the same steps in the
>> > same order and that some of the steps are variables affecting the raw
>> > and rgb data. Some of the settings can be set by the user, some may be
>> > hidden (and proprietary).
>> >
>> > E.g. UFRaw applies white balance, highlight-reconstruction, wavelet
>> > de-noising, raw curve adjustment, gamma and linearity before
>> assignment
>> > of the camera profile.
>> >
>> > Next problem is that the camera sensor does not react fully linearly to
>> > the light - hence an icc profile prepared for a particular
>> > white-balance/raw curve/etc. and used for another
>> > white-balance/curve/etc may provide different result even in the same
>> > raw converter.
>> >
>> > If my understanding is wrong, I would be more then happy to know other
>> > opinions.
>> >
>> > P.S.2 The difference is quite obvious when using Canon's Digital Photo
>> > Professional and UFRaw. There are methods how to find out, which ICC
>> > profiles are used by DPP in MS Windows. However, people were usually
>> not
>> > able to get the same output from UFRaw with those profiles. (I tried
>> > myself and skipped this approach - the Adobe Matrices in dcraw based
>> > converters provide better results).
>> At least theoretically you are wrong in the sense that color management
>> should be independent of MS or Linux or whatever, it's the very sense of it.
>> CM transforms an image from one color space into another by transiting
>> through an ideal color space, it's a mathematical operation not dependent
>> on any drivers.
>> But then there is the question as to whether the CM has been correctly
>> implemented by a specific program or driver.
>
> That is misunderstanding of the previous discussion - while we can
> assume the differences between CM engines are reasonably small, the
> first problem of impossibility to use DPP's ICC profiles for UFRaw lays
> with the fact that different image data are fed to the CM engine. I.e. I
> also agree with your statement (on the theoretical level).
>
> In another words, if UFRaw was able to "develop" the same image data as
> DPP does (i.e. demosaic, denoise, curve, white-balance, whatever
> else...), then we could use DPP's ICC profiles in UFRaw, too.

This is a strong manner to understand CM...

An ICC profile is an undependable OS/software color lut data used in a
standard war to adjust color/gamma/conversion from a color space to
another one.

In this data camera/printer/screen maker set a lots of standardized
information relevant of device. The way to use these information is
described in a CM paper from ICC working group.

Adobe, M$, and some open source project implement these standardization.

In other way, an ICC profile do not depand of an OS/Software !
Personally, i use ICC caera color profile provided from Minolta Win32
program under Linux without any problem.

But, where you has right, some makers as Nikon and Canon, provide ICC
profile with uncomplete or with not standardized data ! ICC profiles
become proprietary and only work with makers software.

This is really weird !

Gilles Caulier
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