Color management question

[Michael Johnson]

I recently bought a colorimeter and used ArgyllCMS to calibrate and profile my
display.  So far I'm quite happy with the results.  However, I don't seem to
have something set up quite right in Digikam, because if I simply export photos
after working with them in Digikam they don't show up properly in
non-color-managed programs, despite being in the sRGB color space (which the
metadata claims they are).

I've discovered that if I convert them to the colorspace of my monitor, however,
they show up exactly right on Flickr and so on.  Even if I strip the profile out
of the files (using ImageMagick), they still look correct.  This makes no sense,
since I'm pretty sure you're not supposed to convert to your monitor's color
space, but perhaps I'm mistaken.

How can I get Digikam set up so that I don't need to manually do this
conversion?

Thanks,
Michael


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

[Remco Viëtor]

on Saturday 08 January 2011, Michael Johnson wrote:
> I recently bought a colorimeter and used ArgyllCMS to calibrate and profile
my
> display.  So far I'm quite happy with the results.  However, I don't seem to
> have something set up quite right in Digikam, because if I simply export
photos
> after working with them in Digikam they don't show up properly in
> non-color-managed programs, despite being in the sRGB color space (which the
> metadata claims they are).
> (...)

In digikam you use the profile you created to correct the displayed image for
viewing. The monitor profile does not and should not influence the data in the
image, but only the way they are displayed.

Non-color-managed programs do not apply your monitor profile to the images.
So, your images will not display the way they do in Digikam. Try having a look
at your images in Digikam with color management disabled (small icon in lower
left corner in Image Editor window).

Converting your images to your profile means that they will look good on your
screen, but probably wrong on anyone else's screen. When you leave them in
sRGB, anyone with a calibrated and profiled screen could see the correct
colours.

Regards,

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

[Michael Johnson]

> From: Remco Viëtor <[hidden email]>
> Sent: Sat, January 8, 2011 10:45:04 AM
>
> In digikam you use the profile you created to correct the displayed  image for

> viewing. The monitor profile does not and should not influence the  data in the
>
> image, but only the way they are displayed.
>
> Non-color-managed programs do not apply your monitor profile to the  images.
> So, your images will not display the way they do in Digikam. Try  having a look
>
> at your images in Digikam with color management disabled  (small icon in lower

> left corner in Image Editor window).
>
> Converting  your images to your profile means that they will look good on your

> screen,  but probably wrong on anyone else's screen. When you leave them in
> sRGB,  anyone with a calibrated and profiled screen could see the correct
> colours.
>
> Regards,
>
> Remco

That's the way I thought it was supposed to work, but it doesn't seem to be the
case with my current settings.  If I don't convert to the monitor profile,
images look right to me in Digikam but look wrong on other computers (or in
non-color-managed programs on this computer).  If I do convert to the monitor
profile, the image's appearance doesn't change in Digikam, but it looks right
everywhere else.  And it doesn't matter if I strip the profile out of the file,
either.

What seems to be happening is that I'm seeing the image through my monitor's
profile, and adjusting it to look right with that profile applied.  But anywhere
that doesn't use the monitor profile looks wrong, because it's not getting the
effect of the monitor profile.

Oh, something that might be important: although I have color management turned
on, when I try to convert to a color profile in Digikam it informs me that "this
image is not color managed".  I'm not sure why it's not, though.  I've looked at
every setting related to color management and can't see what else I would
change.  I've actually been using another color-managed program (Gimp) to do the
conversion, since Digikam wouldn't let me.  If this is the problem, then how do
I get Digikam to treat images as color managed?  (These images are starting as
RAW files in Digikam, and most are not being processed by other programs, so I'm
not sure why it won't color manage them.)

Michael


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

[Marcel Wiesweg]

> I recently bought a colorimeter and used ArgyllCMS to calibrate and profile
> my display.  So far I'm quite happy with the results.  However, I don't
> seem to have something set up quite right in Digikam, because if I simply
> export photos after working with them in Digikam they don't show up
> properly in
> non-color-managed programs, despite being in the sRGB color space (which
> the metadata claims they are).

If digikam applies a monitor profile when showing the images, they will look
different to any program not applying a monitor profile.
If you convert them to your monitor profile, they will look correct on your
monitor with any program, but not on any other monitor (a color managed
program will probably convert so it looks similar, but note the information
loss!)

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