[Digikam-users] A few thoughts about color management

Martin (KDE) kde at fahrendorf.de
Sat Oct 1 21:28:01 BST 2011

Am Samstag, 1. Oktober 2011 schrieb sleepless:
> Hi All,
> A few thoughts about color management to share. Moving from windows
> to Ubuntu brings enough changes to workflow to need a lot of
> adjustments and a heap of dimes for tests prints.
> Why color management is doomed to fail:
> Every surrounding has its own light quality and if we talk about
> outdoor photography the light changes continuously. Your lens does
> some little tricks with the light before it is projected on your
> sensor, which does its own tricks on the light. The camera
> manufacturer applies some profile to make the best of it. Then you
> export it to your computer, which displays your picture according
> the ideas of your your screen cards manufacturer and the profiles
> used at that stage and then forwards it to the screen which
> displays it in his own particular way after using another 
> profile. The image you see highly influenced by the light
> conditions of your room.

I think you miss the point here. I made the same wrong assumptions a 
few months ago.

Photography is NOT the art of reproducing the reality or taking a 
snapshot of the reality, it is the view of the photographer of a part 
of a scene. A photographer uses the camera like a painter uses the 
colours, pens ... during creating the painting. Colour is one (only 
one) part of creating a photo.

Colour management makes sure that the colours I see on my monitor are 
the same (within the limitations of the hardware) on different 
monitors and printouts. If you as the photographing artist wants the 
sky to be red (i.e. as a sign for all the blood of innocent people) 
colour management makes sure that it is the same on you monitor and 
print, but this has nothing to do with the colour the sky had when you 
took the photo.

> Now you start to optimize it with your photo manipulation software,
> which might apply another  profile as well. After that it goes to
> the printerdriver, another profile comes in before sending it to
> the printer, and again some profile comes in, and of course you
> selected your paper which is again a profile.
> Now you have a picture, and if in all those mentioned steps and in
> the steps I forgot to mention everything went well, and you would
> look at it at the same light conditions as you shot your photo, it
> should at least look a bit like reality, although not perfect
> because the paper can not reflect the colors and contrast of
> reality.
> This is the goal of colormangement, but we realy need a lot of help
> of the lord, to have the output look like the input. Besides of
> that, in most occasions we would not be to happy if the pictures
> looked like reality. Out of the context, people will say, ¨oh no
> that sky can never be that red¨, or ¨the water can never be that
> blue¨. If you shoot indoor with usual light, and it has been
> reproduced very well we will experience the pictures as much to
> yellowish and so on and so further.

In technical photography you have to rely on exact reproduction of 
what you photograph. For this you have to profile every step. But in 
real life a photo is no longer a technical only thing. It caries 
emotions, feelings, wishes. It does no longer matters if the colour is 

Just think about all the parameters you can change in taking a photo.
- depth-of-field change by aperture
- movements frozen by the shutter speed
- angle of view chosen by the focal length
All this is part of a highly subjective view of the par I want to 

> A better way:
> Try to set everywhere in your workflow same color profile. This is
> hard, settings pop up or hide in so many places!
> Make a room where the light conditions are optima forma according
> final exposing conditions.
> Compose a test print from different pictures, all colors, shadows,
> highlights should be represented as much as possible. Print and
> view. Make all needed adjustments in your photo management
> software and print again and view. And so on until you have your
> best possible print.

Please don't do this. Calibrate and profile your monitor, scanner and 
printer and that's all you need. And do yourself a favour and take a 
printing-lab that supports colour management, not some of the cheep 
one which do several "optimizations" before printing.

First step has to be calibrating and profiling. It does not mater 
which one first. Do not calibrate any part of your hardware by simply 
looking at it. This does not work. Use special calibration/profiling 

> After this calibrate your monitor so that it relects your print in
> the best possible way.
>  From now on trust your eyes and WYSIWYG.

Never ever trust your eyes. Human eyes neither have a special colour 
setting nor do they have a special luminance setting. The eye looks 
relative. There are few people out there which may see a wrong 
calibrated monitor but they are few. You can see the wron colour if 
you have a test print side by side the monitor, but now what is the 
wrong colour? The monitor or the test print?

I once heard of a test. A german television show setup a piano half a 
tone to high each tone. They took professional piano player and some 
other piano player and let them play on this special piano. Only the 
professional play was able to say that there is something wrong with 
the piano. All other players did not notice the difference. Even the 
professional was not able to say what was wrong.

> Thanks for reading and let me know what you think.

I once took a IT8 target shot every now and then to calibrate my 
camera but I was not satisfied with the results. I double my effort 
but the results keep poor. I partially lost the joy in taking photos. 
Finally I ignore the calibration target and take photos as I like it. 
Only before important sessions I use my grey card to set the white 
point correctly.

As I am a technican I every now and then grab the IT8 target and shot 
some photos to check if the camera setup can be improved but it is not 
that often.

Just my thoughts


> Best regards,
> Rinus

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