Re: Tutorial: Color Management, Camera Profiles,

[Paul Waldo]

Hi Elle,

Great work!  This cleared up a few questions I didn't even know I had! :-)

Quite a number of times, I have gotten the Color Management bug.  I understand
the rationale behind why one uses Color Management but, as usual, the devil is in
the details.  I have never been able to make it all work.  It has been an
unsuccessful struggle to get Color Managed images to look as good as unmanaged
images.  May I propose a topic for installment #2? :-)

I would love to see a step-by-step walk through of how to make Color Management
work in Digikam, including screen shots.  Here are some proposed items for this
walk through:

* Image comparison.  Show an image that was created in a color-managed workflow,
and the same image not color managed.  If the improvement is quantifiable, the
new user will continue reading

* Monitor Profiling in Linux

* Obtain the Camera Profile.  I would suggest gearing the walk through around a
specific camera, so that there are specific instructions or web locations.  This
can be a hugely intimidating task for a new user, so handholding is important
here.  For example,
http://staffwww.itn.liu.se/~karlu/div/howto/ufraw_with_canonSLR.php shows 7
profiles available for a single camera.  What to choose?

* Digikam set up for CM

My camera, where I haven't been able to properly set up CM, is a Canon Digital
Rebel, so if you want to use that for the walkthrough, I wouldn't mind :-)

I think the key is the first bullet point; if you can hook the reader by showing
the benefit, many folks will endure the pain of setting up CM.  If you do want to
use the Rebel as your model, I'll be happy to be the guinea pig!

Thanks for your consideration, Elle!

Paul

On Sun Jun  1 13:12 , elle stone  sent:

>
>   This tutorial on color management, camera profiles, and working spaces has
>been put together in the hope that it will be commented on, corrected, and
>possibly even incorporated into the digikam handbook.  The existing
>information in the handbook is wrong on quite a few counts regarding color
>management, and therefore confusing to a new user. Rather than complain
>about the problems, I thought I would try to offer part of a solution.

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[Elle Stone-3]

Hi Paul,

Bugzilla from [e-mail] wrote

Hi Elle,

Great work!  This cleared up a few questions I didn't even know I had! :-)

Thanks!

Bugzilla from [e-mail] wrote

Quite a number of times, I have gotten the Color Management bug.  I understand
the rationale behind why one uses Color Management but, as usual, the devil is in
the details.  I have never been able to make it all work.  It has been an
unsuccessful struggle to get Color Managed images to look as good as unmanaged
images.  

Could you please email me the details of what you do to produce a "CM image" and an "unmanaged image"?  I am not sure the issue is "color management" per se, but I am really curious and willing to see if I can figure out why your results vary so much.

Bugzilla from [e-mail] wrote

May I propose a topic for installment #2? :-)

I would love to see a step-by-step walk through of how to make Color Management
work in Digikam, including screen shots.  Here are some proposed items for this
walk through:

I would absolutely love to get Color Management working in Digikam.  If you read my other recent posts, you'll see that there seems to be a problem or two with the implementation of digikam color management.  At least it seems so to me, though I haven't ruled out "user error," being a linux newbie and all.

Bugzilla from [e-mail] wrote

* Image comparison.  Show an image that was created in a color-managed workflow,
and the same image not color managed.  If the improvement is quantifiable, the
new user will continue reading

I am not so sure that a color-managed workflow will necessarily lead to an improved image.  If your workflow isn't color-managed, then you are by default working exclusively in sRGB (except for applying the right camera profile, if you are starting with a raw file).  Many, many fine photographs have been produced in sRGB and many professional photographers start with the camera jpeg rather than a raw file.  Color management becomes an issue if/when you want to step outside of the bounds of sRGB as your working and output space.

Bugzilla from [e-mail] wrote

* Monitor Profiling in Linux

A very good topic that I'd be happy to try to write up, especially if people with the newer LCD monitors would speak up about their experiences and procedures.  I'm still using a Sony Trinitron CRT.  When I switched to Linux, being able to calibrate my monitor was my number one requirement, and to my surprise and delight, Argyll does a better job than the windows software I had previously used.

Color management, per se, might not lead to a better image, but I am absolutely positive that using a calibrated monitor will improve your images.  By the way, profiling and calibrating are two different things - you will benefit from calibrating your monitor even if you don't "color manage".  

Let me explain the benefits of monitor calibration by way of examples.  My husband wanted to use a picture I had edited on my computer (using my at-the-time uncalibrated monitor) as "wall paper" for his computer.  Except on his (uncalibrated at the time) monitor, the picture looked a ghastly shade of blue.  I had to deliberately make it look really yellow on my monitor to make it look good on his monitor.  

Another example - I had inadvertently set my monitor to be "too bright".  I spent a lot of time working on the shadow details of a "fall foliage in the city" type of picture.  I sent it to a friend, who reported back that all he saw on his monitor was dark glop.

One last example - now that my monitor is regularly calibrated (CRTs "drift"), images on photography websites look GREAT!  I had no idea how much I was missing out on by using an uncalibrated monitor.  

Bottom line:  if your monitor isn't calibrated, then you really don't know what your images look like!  Too bright?  Too dark?  Too blue?  Too yellow?  Just right?  

Bugzilla from [e-mail] wrote

* Obtain the Camera Profile.  . . . For example,
http://staffwww.itn.liu.se/~karlu/div/howto/ufraw_with_canonSLR.php shows 7
profiles available for a single camera.  What to choose?

Thank you for the link!  I finally found the elusive Canon Rebel XTI 6131 profiles!   I will definitely write up a little "which Canon profile" for you.  

Elle

[Paul Waldo]

----- "elle stone" <[hidden email]> wrote:

[snip]
> Could you please email me the details of what you do to produce a "CM
> image"
> and an "unmanaged image"?  I am not sure the issue is "color
> management" per
> se, but I am really curious and willing to see if I can figure out why
> your
> results vary so much.

The first problem I have is with the camera profile.  I got profiles from the ufraw site I mentioned.  The profiles look great when I convert using UFRaw, but they are very dark when used with digikam.

> I am not so sure that a color-managed workflow will necessarily lead
> to an
> improved image.  If your workflow isn't color-managed, then you are
> by
> default working exclusively in sRGB (except for applying the right
> camera
> profile, if you are starting with a raw file).  Many, many fine
> photographs
> have been produced in sRGB and many professional photographers start
> with
> the camera jpeg rather than a raw file.  Color management becomes an
> issue
> if/when you want to step outside of the bounds of sRGB as your working
> and
> output space.

Agreed that sRGB will work OK, especially if the output medium is sRGB.  My understanding is that if you work in a larger gamut, for some images you will not see artifacts such as clipping and banding when switching to an sRGB output space.  Maybe examples of how that works...?

>
>
> Bugzilla from [hidden email] wrote:
> >
> > * Monitor Profiling in Linux
> >
>
> A very good topic that I'd be happy to try to write up, especially if
> people
> with the newer LCD monitors would speak up about their experiences
> and
> procedures.  I'm still using a Sony Trinitron CRT.  When I switched
> to
> Linux, being able to calibrate my monitor was my number one
> requirement, and
> to my surprise and delight, Argyll does a better job than the windows
> software I had previously used.
>
> Color management, per se, might not lead to a better image, but I am
> absolutely positive that using a calibrated monitor will improve your
> images.  By the way, profiling and calibrating are two different
> things -
> you will benefit from calibrating your monitor even if you don't
> "color
> manage".  

I apologize, I did mean calibration.  I use the KDE calibration tool, but I'm open to anything else.

[snip]

> > * Obtain the Camera Profile.  . . . For example,
> > http://staffwww.itn.liu.se/~karlu/div/howto/ufraw_with_canonSLR.php
> shows
> > 7
> > profiles available for a single camera.  What to choose?
> >
>
> Thank you for the link!  I finally found the elusive Canon Rebel XTI
> 6131
> profiles!   I will definitely write up a little "which Canon profile"
> for
> you.  

Let me know if you need Rebel images.  Thanks !

Paul
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