[Digikam-devel] CMS beginner question

[Thorsten Schnebeck]

Am Freitag 10 Februar 2006 08:56 schrieb fj.cruz at supercable.es:
> Well, are you sure all your photos have a pure white? because
> you have to remember that the "white" color depends on external
> factors, maybe the most importat is the ambient light:
> incandescent, fluorescent, sunlight, flash, etc. Your white
> color, or i have to say what your eyes see as a pure white
> color, is not the same from a color space to another. In any
> case, when you correct the white level you are doing something
> like this: "ok, let's me see what 'white' is the more
> white....ahm, this one, so all the rest have to been adjust
> from this".

Ok, but an RGB12-white is nearly black in RGB16 

> > Maybe the problem is, that we did not talk about format
> > conversion so far but only about device color ranges. Is a
> > PNG-16bit file handled like an output device?
>
> You have to forget all about file formats. A color transform
> using an ICC color profile and a Color Management Engine has no
> relation with the image file format. None of the image file
> formats are handled as any kind of devices, they are only data
> containers. When we talk about devices we mean physical
> devices: cameras, scanners, monitors, printers or film
> recorders.

So, this is my "missing-link" :-) If this does not happen then it 
is clear why applying profiles does not lead to an 
auto-transformation of color levels.

But would this not make sense(?)
I mean, I know the transformed RAW files are way to dark in 16-bit 
so does it makes sense to linear stretch 0-4096 to 0-65535?
Now this starts to leave the area of CMS and is more a DImg raw 
prosessing question :-)

Thanks

  Thorsten