2nd take:

On 12.08.2010 16:16, Graeme Gill wrote:
> yahvuu wrote:
>> I guess pretty much everyone agrees that ideally the color profiles of 
>> imported images
>> should neither affect layer blending nor any tool's characteristics.
>
> The whole point of color profiles is to describe how to interpret the
> device values as visual colors. So a tool that purports to work in a device
> independent colorspace, will (apart from gamut limits) have an effect that
> is not visually affected by the color profiles, but will of course have quite
> different affects on the device dependent values.

yes, on purpose. If i had to put it to a motto, i'd say: "GIMP is about colors, 
not numbers."


>> The only sane way to achieve this is, like James says, to "choose a single 
>> color space
>> and stick with it". This is possible with floating point processing (GEGL).
>> All imported image data gets convert to, say scRGB, processing take places, 
>> and on export
>> data may be converted to a different color space, if necessary.
>
> This would be ridiculous - by misinterpreting the device dependent colors you
> would be applying visual adjustments that differ between images, rather than
> being the same. The fact that you have applied uniform changes to the device
> values is not what you want, since the device values have different meanings
> for different device colorspaces.

OK, here i'm silently presuming that GIMP is fed with absolute color data 
(meaning
that the device color profile is known in case device dependend colors are 
given).
In my regard, that is 'normal operation'.

I consider working with device dependent files (that is, without knowing the 
profile)
a very special case -- that would be like GIMP in 'number mode' instead of 
'color mode'.

If i play devil's advocate, i'd say that GIMP is an image editor, not a 
profiling/calibration
application. GIMP itself doesn't need any calibration. Profiling printers and 
screens should be
done by specialized applications.

Of course, it would be nice if GIMP had integrated support for such user needs, 
but strictly
spoken, it can be done without GIMP (hope i'm right here -- i have no 
experience with profiling/calibration).


As you have explained before, GIMP can be part of the profiling tool chain if 
it is able to export
device dependend files [1]. On the other end (import), i doubt that it is a 
good user interface to
switch GIMP into 'screen calibration mode' by importing such an untagged, 
device dependent image.
Wouldn't it be much better to have a dedicated UI for that? Say, 
Extras->Calibrate Monitor or the like..

The needs for calibration/profiling are important, but should not get in the 
way of everyday work.



But still i don't quite understand the following:

 > This would be ridiculous - by misinterpreting the device dependent colors you
 > would be applying visual adjustments that differ between images,

why am i automatically misinterpreting the device dependent colors?
If the device color profile is known, the conversion to scRGB should do no harm.


 > The fact that you have applied uniform changes to the device
 > values is not what you want, since the device values have different meanings
 > for different device colorspaces.

how could one apply uniform changes 'in meaning' if the device color spaces are 
unknown?


regards,
yahvuu



[1] https://lists.xcf.berkeley.edu/lists/gimp-developer/2010-March/024386.html
     .. and shame on me i missed to send a 'thank you!' for pulling things 
straight in that mail.
_______________________________________________
Gimp-developer mailing list
Gimp-developer@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer

Reply via email to