[Digikam-devel] [Bug 139657] New: Blueish tint in low saturation images converted to CMYK

[Ar]

------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.
         
http://bugs.kde.org/show_bug.cgi?id=139657         
           Summary: Blueish tint in low saturation images converted to CMYK
           Product: digikam
           Version: 0.9.0
          Platform: Ubuntu Packages
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: NOR
         Component: Image Editor
        AssignedTo: digikam-devel kde org
        ReportedBy: ari.reads gmail com


Version:           0.9.0 (using KDE KDE 3.5.5)
Installed from:    Ubuntu Packages
OS:                Linux

This is with Digikam 0.9.0 final.

This is the scenario: I start with an sRGB JPEG image with very low saturation (looks nearly B&W). Open it in image editor, then save it as is as TIFF (8 bits, no compression).

Open the tiff in Krita or in Photoshop. Convert to CMYK. Voila, looks blueish.

Now: open the original JPEG directly with Krita (or photoshop). Save as tiff (RGB, 8 bits, no compression). Now reopen the tiff in Krita/PS and convert it to CMYK. Voila, looks nice, no blueish tint.


I run into this issue the hard way, after carefully preparing my images and then importing them to my Lab's  print order management application, that does some 'softproofing' that actually smells and behaves like CMYK conversion. All my carefully digikam-processed images were blueish!!

With Nikon D80-generated sRGB JPGs, Krita tiffs, Photoshop tiffs, look nice in this app. Digikam tiffs look blueish, totally different from what digikam shows. Maybe a color-profile-related problem?

My workaround is: generate the tiffs with Krita, then continue the workflow on digikam. Seems to work fine (will confirm when the prints are delivered...)

Will attach the original jpg, and two tiffs, one generated with digikam's image editor and the other with krita. All default options. (I played in krita removing alpha channel, changing color space, etc, it always works OK (images never turn blue)).