[Digikam-users] editing with Color Management enabled is very slow?

Jürgen Karbach HJKarbach at gmx.de
Fri Mar 22 16:39:03 GMT 2013

Hello Erik,

thanks for asking. That's what I'm also thinking about quite a while.

Let me ask two  further questions.
     *  Is one of linux's color management systems supporting OpenGL for faster 
     *  Which parts of digiKam7Kipi-Plugins supports OPenGL computing (except 
More out of a bunch questions after having fixed my update disaster on my 

H. Jürgen Karbach

Am 22. März 2013, 09:48:39 schrieb Erik Felthauser:

OS and software: Kubuntu 12.10 with kubuntu-backports ppa (digiKam 3.0.0)
processor: Core 2 Duo T6400 2.0 GHz 800 MHz FSB 2 MB L2 (35 W)
memory: 4 GB - DDR2 800 MHz - 2 DIMMs
monitor colorimeter: ColorHug hardware, with ICC monitor profile set to "High 

I have applied the monitor profile created with ColorHug in two places: in the KDE 
system color settings option, and also in digiKam color management settings. 

My photos are mostly 12MP, JPG or PNG.

When I do not have color management enabled, editing photos is quite fast.
When I turn on color management, editing photos is so slow. Just opening the 
editing window takes fully 5 to 8 seconds. Even just selecting an area for 
cropping, takes 5 second for the system to catch up, and CPU goes up very high, 
50% just for making selection, 100% for other things. Resize the selection area 
takes 5 sec or more.  
Turn off color management again, and everything is fast again. Opening edit 
window is immediate, selection is immediate, etc.

My questions:

1. Since I have set monitor ICC profile in KDE system settings already, can I turn 
off digiKam's own color management, and digiKam will still be showing the correct 
colors for my monitor / profile?

2. If yes to question #1, what working color space is digiKam using when its color 
management option is turned off? sRGB? sRGB-D65?

3. If yes to question #1, then, I think I only need to turn on color management in 
digiKam when I want to do soft-proofing for printer, is that right? (Since I have 
applied ICC in system settings?) 

4. Is it bad to have monitor profile set in both system and in digiKam? Does this 
apply corrections twice, causing over-correction? Or maybe this is why so slow?

5. Why is it so slow to set color management in digiKam? Is my computer 
hardware just too old and slow? If I buy a new computer with Intel i7 processor 
and 16GB DDR3 memory, will it be fast then? Or is the problem that digiKam is 
not yet optimized to be fast with color management editing? 

Thank you very much,


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