digiKam › digikam-users

Can't specify input colour profile

Classic

List

Threaded

4 messages Options

Victor Engmark

Can't specify input colour profile

I've enabled colour management and set the working colour space and
monitor profile. Both of those lists show a whole bunch of profiles,
from /usr/share/color/icc and ~/.local/share/icc according to the
"default locations" pop-up. But all input profile selection lists
("Camera and Scanner", "Printing and Proofing", image editor pop-up
for uncalibrated images) are empty.

I also tried putting AdobeRGB1998.icc into ~/.color/icc. It was
detected but only listed in the output profile selection lists.

digiKam output in case it's relevant (removed repeated lines):

$ digikam
Object::connect: No such signal org::freedesktop::UPower::DeviceAdded(QString)
Object::connect: No such signal org::freedesktop::UPower::DeviceRemoved(QString)
QSqlDatabasePrivate::removeDatabase: connection 'ConnectionTest' is
still in use, all queries will cease to work.
digikam(6346)/digikam (core): Do not use transformForDisplay for
uncalibrated data but let the RAW loader do the conversion to sRGB
digikam(6346)/digikam (core): No input profile: invalid Behavior flags 2097152
digikam(6346)/digikam (core): Do not use transformForDisplay for
uncalibrated data but let the RAW loader do the conversion to sRGB
libpng warning: iCCP: known incorrect sRGB profile

Cheers
V
_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

Remco Viëtor

Re: Can't specify input colour profile

On Saturday 30 August 2014 13:04:11 Victor Engmark wrote:

> I've enabled colour management and set the working colour space and
> monitor profile. Both of those lists show a whole bunch of profiles,
> from /usr/share/color/icc and ~/.local/share/icc according to the
> "default locations" pop-up. But all input profile selection lists
> ("Camera and Scanner", "Printing and Proofing", image editor pop-up
> for uncalibrated images) are empty.
>
> I also tried putting AdobeRGB1998.icc into ~/.color/icc. It was
> detected but only listed in the output profile selection lists.
>
> digiKam output in case it's relevant (removed repeated lines):
>
> $ digikam
> Object::connect: No such signal

org::freedesktop::UPower::DeviceAdded(QString)
> Object::connect: No such signal
org::freedesktop::UPower::DeviceRemoved(QString)
> QSqlDatabasePrivate::removeDatabase: connection 'ConnectionTest' is
> still in use, all queries will cease to work.
> digikam(6346)/digikam (core): Do not use transformForDisplay for
> uncalibrated data but let the RAW loader do the conversion to sRGB
> digikam(6346)/digikam (core): No input profile: invalid Behavior flags
2097152
> digikam(6346)/digikam (core): Do not use transformForDisplay for
> uncalibrated data but let the RAW loader do the conversion to sRGB
> libpng warning: iCCP: known incorrect sRGB profile
>
That would be because the AdobeRGB1998.icc profile is a colour space, not
an input profile.

The difference is that a colour space describes what RGB value corresponds
to a real world colour under a given light source, assuming ideal
behaviour. As real equipment never shows ideal behaviour, we use input and
output profiles to describe where and how the equipment differs from the
ideal case. This means that each input and output profile is specific for
one device, and one device only (for printers, changing paper, ink, or
print settings can make the profile invalid).

To confuse the issue, both colur spaces and in/output profiles are stored
in files with a .icc extension...

So, colour space files can be distributed and used by every one,
independent of the equipment used.

For the input and output profiles you'd have to find one corresponding to
your equipment (camera, scanner, screen) (or, better but taking some time
or money) create your own.

That is also what Digikam tries to tell you (in a rather crytic way)

But, unless you are doing very colour critical work (publicity, scientific
perhaps), you can get away with leaving the input profiles blank.

Calibrating and profiling your monitor and printer is much more important
for most of us:
- the monitor so that others have a fighting chance to see the image as you
intend it to be seen,
- the printer so that the final print corresponds as much as possible to
what your calibrated/profiled screen shows (it will never be exact, due to
the different principles involved: additive RGB vs. subtractive CMYK).

Regards,

Remco

P.S. The libpng warning is a known one btw, try using one of the other
versions easily available until the warning disappears.

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

Victor Engmark

Re: Can't specify input colour profile

Thank you for the excellent answer, Remco. I think I can refine the
question now:

My Canon 7D is set to use the "Adobe RGB" colour space. I have not
been able to find an input profile for this camera anywhere (including
the Canon website). The images generally come out with much more bland
colours than the preview JPEGs.

Cheers
V

On Sat, Aug 30, 2014 at 1:40 PM, Remco Viëtor <[hidden email]> wrote:

> On Saturday 30 August 2014 13:04:11 Victor Engmark wrote:
>> I've enabled colour management and set the working colour space and
>> monitor profile. Both of those lists show a whole bunch of profiles,
>> from /usr/share/color/icc and ~/.local/share/icc according to the
>> "default locations" pop-up. But all input profile selection lists
>> ("Camera and Scanner", "Printing and Proofing", image editor pop-up
>> for uncalibrated images) are empty.
>>
>> I also tried putting AdobeRGB1998.icc into ~/.color/icc. It was
>> detected but only listed in the output profile selection lists.
>>
>> digiKam output in case it's relevant (removed repeated lines):
>>
>> $ digikam
>> Object::connect: No such signal
> org::freedesktop::UPower::DeviceAdded(QString)
>> Object::connect: No such signal
> org::freedesktop::UPower::DeviceRemoved(QString)
>> QSqlDatabasePrivate::removeDatabase: connection 'ConnectionTest' is
>> still in use, all queries will cease to work.
>> digikam(6346)/digikam (core): Do not use transformForDisplay for
>> uncalibrated data but let the RAW loader do the conversion to sRGB
>> digikam(6346)/digikam (core): No input profile: invalid Behavior flags
> 2097152
>> digikam(6346)/digikam (core): Do not use transformForDisplay for
>> uncalibrated data but let the RAW loader do the conversion to sRGB
>> libpng warning: iCCP: known incorrect sRGB profile
>>
> That would be because the AdobeRGB1998.icc profile is a colour space, not
> an input profile.
>
> The difference is that a colour space describes what RGB value corresponds
> to a real world colour under a given light source, assuming ideal
> behaviour. As real equipment never shows ideal behaviour, we use input and
> output profiles to describe where and how the equipment differs from the
> ideal case. This means that each input and output profile is specific for
> one device, and one device only (for printers, changing paper, ink, or
> print settings can make the profile invalid).
>
> To confuse the issue, both colur spaces and in/output profiles are stored
> in files with a .icc extension...
>
> So, colour space files can be distributed and used by every one,
> independent of the equipment used.
>
> For the input and output profiles you'd have to find one corresponding to
> your equipment (camera, scanner, screen) (or, better but taking some time
> or money) create your own.
>
> That is also what Digikam tries to tell you (in a rather crytic way)
>
> But, unless you are doing very colour critical work (publicity, scientific
> perhaps), you can get away with leaving the input profiles blank.
>
> Calibrating and profiling your monitor and printer is much more important
> for most of us:
> - the monitor so that others have a fighting chance to see the image as you
> intend it to be seen,
> - the printer so that the final print corresponds as much as possible to
> what your calibrated/profiled screen shows (it will never be exact, due to
> the different principles involved: additive RGB vs. subtractive CMYK).
>
>
> Regards,
>
> Remco
>
> P.S. The libpng warning is a known one btw, try using one of the other
> versions easily available until the warning disappears.
>
> _______________________________________________
> Digikam-users mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-users

Cheers
Victor

On Sat, Aug 30, 2014 at 1:40 PM, Remco Viëtor <[hidden email]> wrote:

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users

Remco Viëtor

Re: Can't specify input colour profile

On Sunday 23 November 2014 14:36:30 Victor Engmark wrote:

> Thank you for the excellent answer, Remco. I think I can refine the
> question now:
>
> My Canon 7D is set to use the "Adobe RGB" colour space. I have not
> been able to find an input profile for this camera anywhere (including
> the Canon website). The images generally come out with much more bland
> colours than the preview JPEGs.
>
> Cheers
> V
>

For most work, you don't need an input profile for the camera. And digikam
should take care of colour space conversions between image and screen, so
your choice of adobeRGB in camera is not why your images appear bland.

That your images are bland, compared to the previews, usually has other
reasons: the camera applies a range of corrections to the raw data while
generating the embedded jpeg: white balance, black and white point,
saturation, contrast, sharpening, ...

If you develop the raw files yourself, you will have to select proper
values for all of these... (not as bad as it sounds,though).

Perhaps this tutorial could help:
http://www.cambridgeincolour.com/tutorials/histograms1.htm
(and others on that site, there's quite a collection).

_______________________________________________
Digikam-users mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-users