[Digikam-users] Re : Choose another ICC profile for converting pictures

[sleepless]

Hi Remco,

Could you explain this to me this:
If I print from native Windows 7, or from windows XP in Virtualbox on 
Linux or from Ubuntu, and in all setups choose the same colorspaces, and 
the same paper and no corrections or whatever I get tree different prints.
The only decent prints I get without heavy color adjustments on the 
source is in my windows 7 setup, (exactly there where I not want to be) 
with native canon printerdriver.
I lost sofar about 50 A4´s testing for a good result on Ubuntu with 
Turboprint.
Is this the proof that different  software interpreted color profiles in 
there own way, and thus the faillure of colormangement?
BTW In Ubuntu systemwide color mangement does not work at all here, no 
matter which profile I choose, the colors on the monitor never change.

As always TIA for your thoughts.
Rinus

Op 07-10-11 08:20, Remco Viëtor schreef:
> On Friday 07 October 2011 07:31:05 Martin wrote:
>> Am 06.10.2011 21:12, schrieb Paulux:
>>> I've a precision to make : as I understand the Digikam way to manage ICC
>>> profile, it now (I'm sure it wasn't the case in the past) sorts profiles
>>> by type (i.e. the output profiles menu only shows and manages output
>>> type profiles, and so on). That's roughly a good idea for the digikam
>>> control panel, BUT not for the color space conversion tool in picture
>>> editor and batch tool. This one only shows display ICC profiles, but it
>>> should offer output ICC profiles in order to completely control the
>>> colors behavior before print works, especially with remote laboratories.
>> I don't think it is a good idea to convert a photo to the colour space
>> of the printing machine. These profiles should be used for soft proofing
>> only and this has nothing to do with the workspace colour profile (these
>> must not and mostly do not match the display profile).
>>
> ..
> Even worse: screen and printer profiles are NOT colour spaces, but only output
> corrections from a (device-independent) colour space to an imperfect output
> device. They are specific for a combination of a colour space and a device.
>
> A colour space describes how a colour we can see under standardised lighting
> conditions is encoded in an RGB triplet. This is absolutely device-
> independent.
>
> So a colour workspace cannot 'match' a display profile, they are completely
> different beasts and should be used together to get the best output possible.
>
> Yes, I know both colour spaces and device profiles have .icc or .icm
> extensions, but again, they are completely different concepts.
>
> So, please leave your images in the sRGB colour space, unless you REALLY know
> what you are doing:
> a lot of questions concerning dark, muddy, unsaturated colours in prints come
> from people using e.g. Adobe RGB as editing colour space, and then sending of
> those images to a commercial printer (99+ % of those expect sRGB and don't
> check...)
>
> Remco
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